17-Year-Old Child Development Milestones

Your child’s growth and development at age 17.

While many 17-year-olds are looking forward to a bright future beyond high school, others are terrified about entering the adult world. Even parents may find that raising a 17-year-old can be a little scary.

For instance, you may wonder if you have taught your teen everything they're going to need to know to become a responsible adult. To be sure, think about their development and assist them accordingly to make sure they are prepared for the real world.

17 year old child development milestones
Verywell / Emily Roberts

Physical Development

Most males and females are fully developed by their 17th birthdays. They’ve completed puberty and reached their full height. However, boys may continue to develop muscles.

They also may grow more facial and underarm hair and their voices may continue to deepen as well. Body image issues are common at this age as some teens aren’t pleased with the physical changes they’ve endured. Acne also can become common.

Key Milestones

  • Have reached their full height
  • Have completed puberty
  • May continue to see muscle development in boys

Parenting Tip

Talk to your teen about good health, rather than appearance. Keep the focus on eating nutritious food, rather than dieting or bulking up.

Emotional Development

Turning 17 represents an interesting fork in the road for many teens. Some of them take off on a smooth path toward adulthood. They become increasingly responsible and they’re eager to become independent.

Others, however, are terrified of the realities of pending adulthood. Some of them seem lost and confused over the future. They may even struggle to show responsibility with their homework, chores, and daily responsibilities and may feel fearful about becoming an adult.

For the most part, a 17-year-old's moods are calmer than they were in earlier teen years. This is due to fewer hormonal shifts and an increased sense of control. But that doesn't mean teens won't struggle with their emotions when they face a big problem. Whether they're dealing with a broken heart or a college rejection letter, many 17-year-olds are dealing with adult-sized problems for the first time.

Likewise, most 17-year-olds are goal-oriented. They're beginning to imagine what type of life they want to create beyond high school. So be sure you are allowing them the space to figure out who they are and what they want to do.

Key Milestones

  • Show more independence from parents
  • Have a deeper capacity for developing more intimate relationships
  • Take fewer risks

Parenting Tip

Allowing your teen to drive a car, get a job, and stay home alone for the night are just a few steps toward becoming an adult. It's also important to rein them in—especially if they're making poor choices.

Social Development

Most 17-year-olds form strong relationships. They develop close friendships and become less likely to move back and forth between cliques. They also discover that it’s important to be dependable. When they make a promise to their friends, they want to honor their commitments.

Your teen may spend the vast majority of their free time with friends and when they're home, they may prefer to be in their room alone. The parent/teen relationship may shift a little during this age as well. For some, that may mean growing apart from the their parents as they gain independence, but for others, it may growing closer to their parents as their desire to be rebellious fades away.

Key Milestones

  • Search for intimacy
  • Want adult leadership roles
  • Able to make and keep commitments

Parenting Tip

Establish clear rules about dating and talk often about healthy relationships, safe sex, consent, and dating.

Cognitive Development

By age 17, most teens have good organizational skills. As a result, they're able to successfully juggle extracurricular activities, part-time jobs, and school work. But even though many 17-year-olds think they’re adults, their brains still aren’t yet fully developed. So while they may have skills to regulate their impulses, they may still behave recklessly at times.

Most 17-year-olds also are thinking about the future. They begin to establish more concrete plans for college and life after high school. Fluid intelligence also is reached around this age, which means 17-year-olds have an improved ability to cope with new problems and situations.

Speech & Language

Most 17-year-olds can communicate like adults. However, they may not ask for clarification or speak up when they don’t understand a word or the meaning of a phrase.

Slang also is common among teens and may have more meaning than formal language at this age. Meanwhile, some 17-year-olds still struggle to understand double negatives. And although their attention spans are improved, it’s common for them to lose track of long, complex questions.


Play to a 17-year-old might involve going to a restaurant with a friend or it could include engaging in a hobby. Many 17-year-olds engage in similar leisure activities as adults. And most of them have developed hobbies and interests that allow them to relax.

Key Milestones

  • Can communicate like an adult
  • Use slang words often
  • Cope with new problems and different situations better than in the past

Parenting Tip

Encourage your 17-year-old to read for fun. Reading helps build a teen’s vocabulary while also improving their writing skills.

Other Milestones

Seventeen-year-olds may be experiencing a variety of things for the first time. Some of them are getting a driver’s license and a car. Others are getting part-time jobs. Others may be experimenting with some riskier behaviors like unprotected sex, alcohol, or drugs.

And for some teens, age 17 is the first time they experience a serious romantic relationship and perhaps even their first heartbreak. Also, be on the look out for unhealthy dating relationships, including teen dating violence. Many teens struggle to cope with these adult-like issues.

When to Be Concerned

If the thought of sending your 17-year-old out into the real world within the next year terrifies you, you're not alone. Many parents can't imagine their teen navigating the adult world independently. But often, there's a lot of growth between 17 and 18 years old. And within that year, teens become ready to enter college, the military, or the working world.

If your teen seems especially ill-equipped for the realities of adulthood, you might want to talk to your child’s doctor. You also should be concerned if you see major changes in your teen’s mood or behavior. A decline in grades, changes in sleep habits, or a change in weight or appetite are just a few symptoms that could indicate a mental health issue or another underlying problem.

A Word From Verywell

As your 17-year-old moves toward such milestones as high school graduation and the first year of college, you may start to wonder if you have done everything you can to prepare them for life outside of your home. But it's important to remind yourself that it's not too late for teens to learn new skills like managing money, staying safe, and even cooking for themselves.

Proactively look for areas in your teen's life where they might need to sharpen their life skills. As their parent, you play an instrumental role in guiding and teaching them to become the best version of themselves that they can be. And if you run into a few snags along the way, don't be afraid to ask for help from your pediatrician or a mental health professional.

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Article Sources
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  1. Centers for Disease Control and Prevention. Teenagers (15-17 years of age). Updated March 6, 2020.

  2. Coyle TR, Pillow DR, Snyder AC, Kochunov P. Processing speed mediates the development of general intelligence (g) in adolescence. Psychol Sci. 2011;22(10):1265-9. doi:10.1177/0956797611418243

  3. University of Pennsylvania, Penn Medicine. 6 facts parents should know about mental illness in teens. April 11, 2018.

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