irregular period

okay guys so i need help. my period is very sporadic and has been for years. i want to figure out how to make it normal. it doesn't help that i want to have sex with my boyfriend, but because of how irregular i am any time i would be late i would have a panic attack (definitely not ready to be a teenage mom). but i can't get on birth control because my mom won't let me (almost 17). i really need help everyone. any ideas? anddddd go! (i've had my period since i was 12)