No one can say exactly when you'll get your first menstrual period, but it will be sometime during puberty. Puberty is the time in your life when you begin to become an adult. This means a lot of growing and changing — both inside and out.

Some girls start puberty at age 8, and others may start as late as 13 or 14. Each girl goes at her own pace. So don't think you're weird if you start puberty a little earlier or a little later than your friends.

At the beginning of puberty, you'll notice that your breasts are developing and hair will start to grow on your genitals (pubic hair). A little later, hair also will grow under your arms.

For most girls, their first menstrual period, or menarche (say: MEH-nar-kee), begins about 2 years after she first starts to get breasts. For most girls this is around age 12. But it can be as early as age 8 or as late as 15. Talk to your doctor if your period started before age 8 or you are 15 and haven’t started your period.

A good sign you're getting close to the time when your first period will arrive is if you notice a discharge coming from your vagina. It might be thin and slightly sticky or thick and gooey, and can be clear to white or off-white in color. Usually, this happens about 6 months before you get your first period.

If you think you're getting close to your first period, it might make you more comfortable to be ready. Put a pad and change of underwear in your backpack or purse in case your period comes when you aren't at home.

Are you thinking a lot about when your first period will come? You're not alone. Lots of girls wonder and wonder — when will it come? If you feel a little worried or nervous about getting your period, it can help to talk to someone you trust, like your doctor, mom or older sister.