Girls typically begin puberty between ages 8 and 13. Puberty is the time when your body goes through hormone changes, your breasts develop, you notice pubic hair, and you have a growth spurt. Every girl is different, so it is completely normal for some to begin puberty before 8 years old or even occasionally after 13 years old. Once a girl begins puberty, about 2-3 years later they begin their periods. Most girls begin their periods between ages 10 and 14 years old. Since you are 17, it would be important for you to schedule an appointment with your primary care provider. They can discuss different reasons why you haven’t started your period yet.