I'm going on holidays in june and im on my period but my mom said it would be dangerous to delay it because i'm only 16 and have a short cycle (20day?

Ur mom won't like me: You're planning ahead! So your mom won't like me, or at least my answer, but there's no health risk w/delaying your period, regardless of your age, assuming you're not pregnant or undergoing oopherectomy. Some birth control pills are sold in such a way as to minimize one's menses. You can do same by skipping sugar pills & starting next pack immediately. Of course, discuss this w/your doc & mom!!!!