Birth control means things you can do to ensure that pregnancy only happens if and when you want it to.
Birth control can mean abstinence.
Abstinence is deciding not to do something, and abstaining from having sexual intercourse will ensure that pregnancy does not occur. Birth control can also mean using a method of contraception to ensure that pregnancy does not occur when you do have sexual intercourse. Usually, sometime between the ages of 11 and 15, a girl begins to have periods. This shows that the ovaries have begun to produce eggs. An egg is released every month.