I live in florida, and here you don't have to be with your parent to have the doctor put you on birth control. I would talk to your regular doctor, or find the local health department for your state, there is usually one in every town, and go there. They will not only put you on birth control, if your state allows, but they will do it for very little $ or for nothing at all, and will pregnancy test you while you are at it.
I am the mom of a 14 year old girl, who against my wishes is sexually active. When she came to me and asked me to put her on the pill I did in a split second, I would rather her be on the pill, then get pregnant as young as she is. I know better than to believe that she is not going to have sex, yeah right!