Sometime between ages 9 and 13, most girls go through puberty, a process that, in essence, changes your body from a child to an adult. Both boys and girls go through puberty.

For girls, �breast budding� is usually the first sign that they�ve entered this exciting, but sometimes scary time. You�ll notice slight changes in the size and shape of your breasts as they begin to grow.

Mood swings might follow. You might feel happy one second, sad and angry the next � without having any idea why you�re feeling that way. Blame the hormones. They�re surging through your body and making you feel a little crazy sometimes.  It�s normal. Hang in there. It�ll pass.

You can also blame the hormones for changes in the sweat and oil glands, which makes
for blemishes and body odor. (Enter deodorant.) Hair will also begin to grow under your
arms and around your vulva. The hair on your legs will become more coarse and dark.
And your body will become more �womanly,� with wider hips and larger breasts.

Inside, the uterus, cervix, and ovaries are growing and maturing, too. Usually sometime in the middle of puberty, girls get their first menstrual period.  While most adult women
have a period about once a month, most girls have irregular periods during the first year
or two of their menstrual cycles. Some women will always have irregular periods.