birth control

So I'm 17 and I've been in a relationship with my boyfriend for 9 months and we haven't had sex but if the opportunity comes along I wanna be prepared. My stepmom and I have talked and she works with teens and she knows how we are and she wants me on the pill. And it's not that I don't trust her (I feel more comfortable talking to her about that stuff than with my own mom) but I guess I'm just scared to tell her. Or bring it up. How do I ask her to help me get on it or where can I go to get it besides my doctor (my doctor is actually a family friend of my mom... I know weird) I know of planned parenthood, I just have no idea how it works. PLEASE HELP!