My daughter wants to be on birth control

My 16 year old daughter had approached me about birth control. I told her I'd schedule an appointment and I have for this up and coming week. I am proud of her for being honest and taking steps to prevent pregnancy, but I am also worried. I don't know what this means now. I have rules set in place that don't allow her and her boyfriend to be alone at home. And neither of them have cars. I feel like I shouldn't wonder, but where are they planning on having sex? Do they expect our rules to change? Do I change the rules? I don't know what to do. I always said I'd be accepting and understanding when this time came around, and I am, but I'm struggling with it. My daughter is great. So is her boyfriend. They are both very mature, responsible, and respectful. But I can't help but feel a little sour about this. Any other moms dealing with this? Any advice? Thanks. Also, sorry, I'm not sure which category this should go in.