Lots of girls and guys worry about when their bodies will develop. Guys wonder when their voices will get deeper, when they'll need to shave, or when their penises will grow. Girls want to know when their breasts will develop or when they'll get their first period. If a friend or a younger brother or sister develops first, they may worry that there's something wrong with them.

The fact is that physical development starts at different times and progresses at different rates in different people. So, the beginning of the development that comes with puberty varies from person to person - and that's completely normal.

The earliest physical change of puberty for girls is usually breast development, which most often begins around 10 or 11 years. But it's perfectly normal for breast development to start anytime between the ages of 8 and 13. A girl's first menstrual period usually occurs about 2 years after breast development begins.

Boys begin their development on average around age 11 or 12, but it's also normal to begin anytime between the ages of 9 and 15. Girls and guys who start developing earlier or later than these ranges can still be normal, but they should be checked by their doctor just to be sure.

For both boys and girls, it usually takes several years after the first changes of puberty begin before they're all complete - and there's a lot of variation from person to person. So, two normally developing guys or girls who are the same age can appear quite different from each other. One can look older and more physically mature than the other. But the one who started later will catch up in time.

Can I Do Anything to Speed Up Development?

You can't do anything to make your body develop faster. Of course, you should eat a nutritious diet, exercise, and get enough sleep. But special diets, dietary supplements, or creams won't do anything to make normal puberty happen quicker.

But some unhealthy things can interfere with development. Steroids, like those used for bodybuilding, can cause problems with growth, shrink testicles (and lead to breast development) in guys and shrink breasts, disrupt menstrual cycles, and cause excessive hair growth in girls. (Steroids can cause other serious health problems, too.) Girls who have eating disorders or who exercise compulsively may delay their development and hurt their health. A number of medical conditions can also delay puberty and development.

If you're a girl who's 13 or older or a boy who's 15 or older and you haven't shown any signs of puberty (or if you're younger but are still worried), talk with your doctor. Most of the time everything is just fine, but the doctor can determine if there's a problem. And if there is a problem, there's almost always treatment available that will help you develop.