birth control?


i am 15 years old and just got into a relationship. i really want to get on birth control for my period because my cramps are almost unbearable, i get so nauseous, and my flow is so inconsistent. i don’t know how to ask my mom because i’m scared she is going to assume i am having sex and not trust me. my 18 year old sister is on birth control and suggested it because she said it helped her a lot.