A girl's breasts and pubic hair begin to grow, sometimes as early as age 8.
Puberty is also the time that girls have their first period.
Like many girls, you may be curious about what to expect. This information will help you to better understand your periods and answer some of your questions. Remember that your health care provider can answer any questions or concerns you may have about your period, or other changes you're going through. During puberty, chemicals, called hormones, signal your ovaries to make estrogen and other hormones that cause your uterus to grow. Hormone levels change throughout each month, causing the lining of the uterus to get thicker.