Birth Control

No judgement please. I'm 17 and previously my mother has taken me off of my birth control when she found out me and my boyfriend had sex. I was originally on birth control to control my menstrual cramps and now since I'm off they have been getting worse and harder to control. What do you think is the right age to be put on birth control? My mother will not let me get back on it due to the sexual activity but I really need it for my cramps. What are your opinions... When is the right time I should ask again?