Asking my mom about birth control

So, I asked my mom last night if I could get the birth control shot. She said we could talk about it later, but I'm really nervous about it. I kinda lied to her about being a Virgin, and I don't plan on telling her I'm not for quite a few years. I don't want to use the shot as an excuse to be extra wild either, though. What do I say? What do I do? I sent her this text last night: 
Mama, I'm thinking about getting the birth control shot. The Depo-Provera. I know this is a horrible, terrifying, and very awkward topic. But I think it's important to be protected and prepared for the worst. You have been questioning me about my virginity and I will tell you, I still am a virgin and intend on remaining one for a while, but I just want to be prepared and protected. Just for state of minds sake I guess you could say. I've done my research and have been thinking about it for some time now, and I think it's not a bad idea.