How do I get Birthcontrol

Ok, it maybe a stupid question, but I've been dating this guy for almost a year now, my parents like him, I'm in still in love with him. We have done "things" in the past, and we have had sex many times before. I'm 15, and not on the pill, I have brought it up to my mom, but she's still hesitant of getting me on the pill, she doesn't know we had sex or anything, but I don't know how to get her to let me go on the pill. I'd feel better if I was on it, even though we do use condoms. Any suggestions?