sex, mom doesnt know, birth control

Okay so im 15, and have been having sex for about a year now. As of recently (4months) it's been more frequently (with one partner). We seldom use condoms because it's usually quickies, and he never finishes in me.

But my mom doesnt know I've been having sex, and I feel as if I should start birth control. How do I get her to schedule an appt for it without letting her know I've lost my virginity?