asking for birth control

hi everyone, so im 14 years old soon to be 15 and I live with my dad and stepmom. I have dealt with bad period cramps for the past year now (I got my period September 2016). I have tried almost every relief for them but they don't help. I was recently talking to some of my friends who were on the pill and they said it helped a lot with their cramps. After looking into this and doing extensive research I think it would be a good thing for me to try but the problem is how do I ask my parents to go on it withou

t freaking them out?