13 - 18 years

Developmental Milestones for Teens (13–18 Years)

Learn about the critical social, physical, and cognitive milestones for teenagers from 13 to 18 years, along with red flags to watch for in this year-by-year guide.

Jessica Guht

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During the grade school/preteen years, your child’s world started to expand outside of your house. They learned how to manage schoolwork and how to form friendships. Their time in school has also increased their skills in math and language, teaching them how to apply basic mathematical operations, use grammar rules, and create stories. 

As your child enters their teen years, their social development will continue expanding, with their friendships becoming more important than ever, eventually overtaking your relationship with them. Don’t fret, though, because that won’t last forever.

You also have puberty in store for these teen years, which can bring along body image issues, mood swings, and rapid physical changes. This is when your child’s independence shines through, though, as they prepare for life after high school. 

To help you navigate the teenage years, we have compiled a list of milestones for ages 13-18. 

13-Year-Old Milestones

Your child has officially entered the teen years, and by this age, you’ll notice some significant developments. For instance, your thirteen-year-old is starting to develop their own opinion of the world around them, although they may still use their friends and social media to form these opinions. 

Your teenager’s body is also changing significantly as they start puberty, and they may begin to notice how their changing body differs from their friends. 

Here are other milestones your 13-year-old can expect to hit in their first year as a teenager:

Speech and Language

  • Uses metaphors
  • Uses slang and text-speak
  • Has discussion, debates, and arguments
  • Begins paying more attention to body language, tone of voice, and other nonverbal cues
  • Starts using writing to describe personal experiences


  • Only shows additional improvements in their motor skills if they are training for a sport or if a hobby requires them
  • Becomes a little less coordinated as height and weight change quickly
  • Starts showing uneven development in skills like balance, agility, flexibility, and strength (e.g., can run fast but not gracefully)


  • Is insecure
  • Experiences mood swings (more pronounced in girls)

Thinking and Reasoning

  • Goes through “what if” scenarios and talks through different ways of problem-solving
  • Starts predicting the consequences of actions and plans accordingly
  • Can argue more than just one side of an issue
  • Begins relying on friends and social media to get information and form opinions
  • Starts understanding how things are connected
  • Starts understanding the concepts of power and influence
  • Thinks about how current actions affect the future


  • Is uncertain about puberty and its changes to their bodies
  • Is increasingly independent from family — withdraws more from family activities
  • Develops a better sense of responsibility and helps out around the house
  • Begins developing a worldview and a basic set of values


  • Tests limits and pushes boundaries
  • Forms stronger and more complex friendships
  • May face intense peer pressure
  • May test out new clothing styles, mannerisms, and attitudes while figuring out how to fit in

13-Year-Old Developmental Red Flags

If you notice any of the following in your 13-year-old, or if you are concerned about their behavior, reach out to your pediatrician:

  • Has changes in sleep patterns
  • Excessive isolation
  • Excessive anger
  • Impulsive behavior
  • Excessive risky behaviors
  • Secretive behavior
  • Loss of interest in activities they once enjoyed

14-Year-Old Milestones

At 14 years old, your child has some strong preferences, and they’re not afraid to let them be known. They also have complex thoughts and may start thinking of the world beyond their community. 

Even though their communication and ability to express their emotions are growing, you may find that they’re less communicative with you. Instead, they may prefer to confide in their friends. Still, while they may never admit to it, 14-year-olds love to know that they can always come to you!

Here are the developmental milestones you can expect in your 14-year-old:

Speech and Language

  • Can better express feelings through talking


  • May experience concerns if they develop physically slower than their peers
  • Most girls have started their menstrual periods
  • Girls have begun developing breasts
  • Boys have seen an enlargement in their penis and testicles


  • Shows more concern about body image, looks and clothes
  • Focuses more on themselves, alternating between high expectations and lack of confidence
  • Experiences more moodiness
  • Experiences stress from more challenging schoolwork

Thinking and Reasoning

  • Has a greater ability for complex thoughts
  • Has a stronger sense of right and wrong
  • Can focus on the future


  • Starts to set personal goals
  • May challenge the solutions and assumptions presented by adults
  • Is embarrassed by parents
  • Recognizes own strengths and weaknesses


  • Shows more interest in peer groups
  • Influenced by peers
  • Shows less affection toward parents; may even be rude or short-tempered
  • Wants to be liked
  • Displays interest in romantic relationships

14-Year-Old Developmental Red Flags

Every child is different, but contact your pediatrician if you notice the following in your child:

  • Falling behind academically
  • Drastic mood swings
  • Changes in eating habits
  • Excessive worrying or fear
  • Poor self-care
  • Aggression
  • Low self-esteem

15-Year-Old Milestones

This is when your child begins developing the skills they need to become a young adult. Not only are 15-year-olds taking on more responsibilities and navigating the workload and social landscape of high school, but they’re also increasing their confidence in their self-identified strengths.

However, as your 15-year-old’s skills grow, so will their belief that they know everything, which can result in a trying attitude for their loved ones to navigate. 

Here are the other milestones you can expect in your 15-year-old:

Speech and Language

  • Can communicate in an adult-like fashion
  • Can hold appropriate conversations
  • Can tell more involved stories
  • Uses slang when speaking with their friends


  • Boys may continue growing, but most girls have reached their full height
  • Boy’s voices become deeper and they may begin growing facial hair
  • Boys may gain muscle rapidly


  • Many girls are insecure about their appearance
  • Have greater emotional regulation skills
  • Have a deeper capacity for caring

Thinking and Reasoning

  • Shows more concern about their future
  • Exhibits more defined work habits
  • Can explain the reasoning behind their choices


  • Has specific hobbies or interests
  • Shows a greater respect for the rules when their privileges depend on their behavior


  • Prefers to communicate through text messages and social media
  • May struggle with peer pressure
  • Has a strong interest in romantic relationships

15-Year-Old Developmental Red Flags

You know your child better than anyone, so if you are ever concerned about their development, mood, or attitude, reach out to a pediatrician. Additionally, keep an eye out for the following:

  • Sleep problems
  • Frequently isolating themselves
  • Changes in eating habits
  • Excessive anger or aggressiveness
  • Drastic mood swings
  • Poor academic performance
  • High-risk behaviors
  • Substance use
  • Abandonment of friends

16-Year-Old Milestones

The teenage years continue at 16. By this age, your child is likely starting to drive, whether with a permit or a full-fledged license. Not only is this, on its own, nerve-wracking, but this newfound freedom also comes with an increasing need for independence, which can cause your teenager to act out toward you. Just remember, the teenage years don’t last forever!

Your 16-year-old is also starting to consider what they want to do in their future. For those interested in attending college, this is when you may start taking them to visit colleges or help them prepare for standardized tests.

Here are the other developmental milestones for your 16-year-old: 

Speech and Language

  • Is more abrasive and sometimes rude when talking
  • May be less communicative
  • Seems to love arguing
  • Changes their language and behaviors between school and home


  • Has the visual-spatial coordination needed to judge distance and speed and react quickly when driving
  • Boys may still be developing, with more height growth and further development of facial hair
  • Experiences a redistribution of fat patterns
  • Sleeps and eats more to keep up with growth
  • Is more agile and coordinated


  • Regularly sulks
  • Develops a better sense of compassion for others
  • May be concerned about the way they look

Thinking and Reasoning

  • Has preferred methods for studying
  • Plans for future school or work
  • Can better reason out a course of action and explain their decision
  • Memorizes information more easily


  • Is more emphatic when expressing opinions
  • Shows signs of confidence
  • Begins making decisions with their independence in mind
  • Begins developing a worldview and a basic set of values


  • Is part of a team or clique (or wants to be)
  • Shows more signs of sexual interest
  • Becomes aware of sexual orientation
  • Enters into deeper platonic or romantic relationships
  • Has increasing resistance to peer pressure
  • Begins relating to family better

16-Year-Old Developmental Red Flags

It can be hard to identify what is normal for a teenager, and what isn’t. Contact your pediatrician if your 16-year-old displays any of the following:

  • Increased isolation
  • Irregular sleeping patterns
  • Loss of interest in things they once enjoyed
  • Loss of self-esteem
  • Unexpected and dramatic decline in academic performance
  • Weight loss

17-Year-Old Milestones

At 17 years old, your child is likely looking forward to what awaits them after high school, but they might also be apprehensive about entering the adult world. It’s common for you, as well, to experience stress and uncertainty as they approach adulthood. 

In good news, your 17-year-old is good at communicating and can explain any concerns they may be feeling so that you help them through. You can also look forward to fewer conflicts between you and your teenager, bringing back some of the peace.

Additionally, puberty is starting to ebb away at 17. Most girls have reached their full adult height and have the body of an adult woman, while some boys may still add on the last few inches in height and some more muscle. 

Here’s the list of developmental milestones for a 17-year-old:

Speech and Language

  • Can communicate like adults
  • Commonly uses slang
  • May still struggle to understand double negatives
  • Can lose track of long, complex questions


  • Girls have completed puberty, while boys may still be maturing physically
  • Metabolism has slowed to more adult ranges
  • Acne can become common
  • May experience body image issues


  • Has a deeper capacity for caring and sharing
  • May feel a lot of sadness or depression
  • Can cope with new problems and different situations better than in the past

Thinking and Reasoning

  • Has more defined work habits
  • Is better about giving reasons for their choices, including what they believe to be right or wrong
  • Understands that their decisions have long-term effects
  • May still do things without thinking first
  • Organizational skills improve


  • Shows more independence from parents
  • Shows excitement and/or concern about future school and work plans
  • Wants adult leadership roles
  • Can make and keep commitments


  • Has more interest in romantic relationships
  • Has fewer conflicts with parents
  • Develops more intimate relationships
  • Spends less time with parents and more time with friends
  • Searches for intimacy

17-Year-Old Developmental Red Flags

As your teenager keeps maturing, keep an eye out for the following warning signs:

  • Excessive sleeping
  • Unexpected decline in academic performance
  • Poor self-care
  • Lack of interest in what they used to enjoy
  • Signs of substance abuse (e.g., smell of smoke, bloodshot or watery eyes, secretive behavior, irritability)
  • Excessive moodiness
  • Obsessive body image concerns
  • Extreme anger

18-Year-Old Milestones

Your child is officially an adult. The baby that once had to learn to walk is now forming their own opinions, working through decisions, and has plans for their life after high school. 

Just because 18 is when they are officially deemed an adult doesn’t mean they won’t still benefit from their parents, though. Still, this is a tricky time where you guide your teen toward autonomy while also trying to do what you can to keep them safe. 

For the final year, here are the developmental milestones for 18-year-olds:

Speech and Language

  • Can communicate like other adults, although may say the first thing that comes to their mind without thinking it through
  • May seem less communicative


  • All genders have reached their full height
  • Establishes their body image
  • Less preoccupied with body changes
  • Takes care of their own personal hygiene and grooming


  • Has an increasing capacity for using insight and empathy
  • Shifts their emphasis from self to others
  • Can manage emotions in a socially acceptable manner

Thinking and Reasoning

  • Will move into adult roles and responsibilities (e.g., learning a trade, working, or moving on to higher education)
  • Fully understands abstract concepts and is aware of consequences and personal limitations
  • Builds and tests decision-making skills
  • Often philosophical and idealistic


  • Identifies career goals and prepares to achieve them
  • Is secure in their autonomy
  • Develops new hobbies, skills, and adult interests
  • Carries some feelings of invincibility
  • Can make their own schedule and plans
  • Can evaluate their own opinions instead of following those of others
  • Sets limits and compromises when appropriate
  • Is more comfortable seeking adult advice


  • Moves into adult relationships with their parents
  • Sees their peer group as a less important determinant of behavior
  • Has greater intimacy skills
  • Enters into intimate sexual and emotional relationships

18-Year-Old Developmental Red Flags

Just because your child is an adult doesn’t mean they don’t need their parent to help look out for their well-being. Keep an eye out for any of the following warning signs in your child:

  • Red eyes
  • Pays less attention to personal grooming
  • Loss of appetite
  • Unexpected changes in school or athletic performance
  • Overly withdrawn from family
  • Volatile mood or attitude
  • Lack of concern about the future
  • Low self-esteem
  • Changes in sleeping patterns
  • Paranoia
  • Self-mutilation
  • Abandonment of friends and social groups

Find the Best Care for Your 13–18-Year-Old Teenager

As puberty hits, your teen will delve further into their social relationships, forming stronger friend groups and even showing interest in romantic relationships. However, if something is wrong, we know you want to get them the best possible care. 

At Coral Care, we will help connect you with the pediatric care your teen deserves, whether that’s a physical therapist, occupational therapist, or speech language pathologist. Let us help you find the best care for your 13 to 18-year-old today!

Find effective support for developmental delays, quickly.

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In-person and at-home appointments
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Get Started