When you're a teen, your body changes — on the inside and the outside. This is part of growing up. It's called puberty.

What Is Puberty?

Puberty is when a person's body changes from a kid to an adult. Girls become women. Boys become men. The changes of puberty happen slowly.

When things change, it can feel a little scary. Knowing what to expect can help you feel better. When you have questions, ask your mom, dad, doctor, or another trusted adult.

How Will My Body Change on the Outside?

During puberty, you will get:

• taller
• oily skin and pimples
• breasts. Just like people come in many shapes and sizes, so do breasts. There's no one right size for breasts.
• hair on body parts other than your head. It will grow under your arms, on your legs, and your private area (the part covered by underwear).
• sweat that smells stinky — especially under your arms

These changes are normal and healthy.

How Will My Body Change on the Inside?

It might not seem like it, but a lot is happening on the inside too. The biggest thing that happens is that you will get your period (called menstruation).

This is when blood comes out of your vagina, but you are not sick or hurt. When you get your period, you will see blood on your underwear, on toilet paper, or in the toilet bowl. Girls can wear a special pad in their underwear to catch the blood. Some girls wear period underwear. It’s just like regular underwear but has a built-in pad to catch the blood. Some girls use tampons. A tampon is put into the vagina to soak up the blood.

Periods usually happen once each month and last for 3 to 7 days.

When you have your period you may feel cranky, tired, or sad. Some girls get stomachaches. If your stomach hurts or you're not feeling well, always tell your mom, dad, or school nurse.

How Will I Feel?

Puberty might cause strong emotions, like feeling angry. You may have other feelings too:

• You might feel happy one minute and sad the next.
• You might think another person is cute, and like them a lot.
• You might feel like touching yourself in your private area.

These feelings are normal and part of growing up.

What's Private?

Private means when you are alone. Your bedroom and the bathroom are private places. You also have private parts of your body, which are covered by your bra and underpants. Some of the changes that come with puberty need to be taken care of in private.

What to Do in Private

It's OK to touch your private parts when you are alone in the bathroom or your bedroom with the door closed. Do not touch your private parts when in public. Public places are where other people are around, like a classroom, restaurant, or playground.

Your mom or dad or doctor may need to check your private area to keep it clean and healthy. No one else should touch your private area, and you should never touch another person's private area. If anyone (even an adult) ever touches you or your private area in a way that makes you feel bad, say "No!" and tell your mom, dad, or other trusted adult.

When you are older and ready to have a boyfriend or girlfriend, talk to a parent, doctor, or other trusted adult to learn about sex and healthy relationships.

Changing your pad. When you get your period, you will need to wear a pad or tampon to catch the blood. You have to change your pad before it smells or is full of blood. Changing your pad is also something you do in private. Your mom, dad, or another trusted adult can teach you how to use pads or tampons.