how to talk to my mom about birth control

so a little back story ig i’m 16 and i’ve been sexually active for a little over a year and i wanna go on birth control for multiple reasons intense period cramps, heavy periods etc my mom also got pregnant at 16 and it’s a big fear i have but i don’t really want her to know i’m sexually actively but she thinks i’m just being a big baby about how bad my periods are when i literally sometimes can not get out of bed can someone help me and how i go about this to her ?