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!

I am 14 and I do not have my period yet. I have been in a relationship with a guy for 4 months, and feel ready to have sex, but I don't know what do since I don't have my period. Help?