Puberty starts for girls around eight, nine and ten. It starts for boys a little later, around nine, ten, 11. If you notice different changes that you are experiencing, you may be going through something called precocious puberty, so look in the mirror.
If you're a girl about seven, or younger, and you notice any hair on your upper lip, if you have breast development, if you have underarm hair or pubic hair, if your body is starting to change shape, you're a little curvier, gaining weight. Or if you're a boy and notice some of these changes, like hair on your upper lip, your voice is starting to change, you have underarm hair, you have some changes in your genital area, you may be developing sooner than most people your age. And this is called precocious puberty.
Precocious puberty tends to run in families. It's more common in girls than boys, and it's more common in overweight girls than it is in girls of normal size. Usually there's nothing wrong if you're developing a little bit earlier than your friends. But sometimes it could be the sign of something going on, something like hormone issues, or a side effect from a medication.
It's a really good time to speak to your parents if you have any concerns, and your parents can make an appointment with your doctor. The doctor can refer you to someone called a pediatric endocrinologist. And that's a specialist who deals with children and specializes in hormones and growth issues.
But don't worry. Everybody develops at their own pace, and everybody and your friends will catch up with you in no time.