Your body has been constantly changing since you were born. During adolescence, the changes your body undergoes will be more rapid and dramatic than at any other time in your life, except for the first year after you were born. These changes can be scary, but also exciting. Either way, it's best to understand what is happening to your body so that you'll know what to expect.

Puberty is the term used for the time when your body is changing from the body of a child to the body of an adult. This process begins earlier in girls than in boys, usually between ages 8 and 13, and lasts 2 to 4 years.

In the early part of puberty, your brain sends signals to your ovaries (reproductive organs in your lower abdomen) to begin producing a hormone called estrogen. The estrogen you produce and some other brain chemicals signal your body to start growing and changing into your adult body.

Since you're going through so many changes at once, you might find yourself wondering, "what's normal?" So, let's take a better look at how your body is developing and growing.