I'm 19. Is it Normal to Still Have Irregular Periods?

I'm 19 years old and my period has been irregular since I first got it 5 years ago. Is this normal?
– Clare*

It is normal to have irregular periods for the first few years of menstruating — and sometimes even longer. But the only way to know if everything's OK is to visit your doctor or . The length of a menstrual cycle can vary from girl to girl, but on average they're usually between 21 and 35 days.

A number of things can cause irregular periods: A girl may have something going on with her . Excessive exercise, not eating enough calories, or being underweight or overweight can also affect a girl's cycle. So can medicines or drugs (like steroids).

Because you've had irregular periods for more than 3 years, see your doctor or nurse practitioner to find out what's causing them. He or she may be able to prescribe medicines to help correct a medical problem. Or, if things like exercise or eating habits are behind your irregular periods, your doctor may give you ideas for some changes.

*Names have been changed to protect user privacy.