Ok, I'm almost 14 and I have not started my period yet. I'm short (4 foot 11 inches) and I don't know if that would affect me not having it yet. I have cramps like the ones you would have before your period but then...nothing. I'm an active person, but normally active, not overly active and not a couch potato. All of my friends at school have already started. Although I'm glad I don't have to worry about something else in my life, I don't know if its normal or not for me not to have my period. Please help, thanks!

You say you're short, but are you also lightweight? The female body has a weight minimum it needs to meet before it will start menstruation. If you're too small, your body is going to conserve its resources and you're not going to have a cycle.

Do late bloomers run in your family? Ask your mom when she started her period. If she was late, too, chances are you will have to wait.

You're still 13, so you're not out of the realm of normal. If you do not yet have a menstrual period by the time you're 17, then see a doctor and ask what's up. Or feel free to ask at your next appointment.

Either way, I think you're okay for now. But if you really want to know, you can have your doctor examine you.