oh man, you should just like me! i hardly ever get my period, and i got it when i was 14. it's never been regular since. i probably only get mine about 3-4 times a year. when i do get it, it only lasts for 2 days, and it's never heavy. i used to get cramps, but when i got to college, they never came back. i strongly suggest you talk to your gynecologist just so she can see what's going on, and if there is anything to worry about. i'm sure you're perfectly fine, but it's definitely beneficial for a check out.
my gynecologist suggested i'd take some medication to get my period back on track, i think you should ask yours about it!
