The number one way to solve your problem is to talk to her. Have a serious discussion about whether she is ready or not, and be prepared to accept both a no or a yes. It might hurt her the first time, and make sure that you both are aware of the risks and the emotional investment that sex can create. If you are worried that she has an STD, ask her to get tested, in the nicest and most considerate way possible. Good luck to you both!