Unless your sperm are made of magma, I think you're safe. I understand the paranoia, especially for guys who get zero say in a pregnancy. Definitely make sure you are in charge of the condoms, though - some women will lie about being on birth control and poke holes in condoms so they can get pregnant. Don't let her have access to your rubbers just in case.
But yeah, I think regardless of whether or not she's on birth control, the condom and pulling out with that condom still on are just fine. I've been using those two methods alone for five years with my guy and is has not failed us. Relax and enjoy the intimacy with Ms. Right Now while you can.