cheyanne, i used to have that problem!!! i went for about 1 year without af and im only 22!!! doctor told me i had PCOS.

went on metformin and spyronolactone (for awful body hair associated with pcos), lost 10 pounds, got married, and BAM! im pregnant! lol maybe go to your doctor if it continues? could be something serious... dont make me worry!! :-)