As others have said, tell the truth. Its nothing to be ashamed of. Everybody got to have a first time.
Also, for all you know, most of your friends may be lying about having had sex, or at the very least exaggerating.
If you can't communicate with this girl, its not worth having sex with her. If you can't talk to someone about it, and be honest, THAT is whats going to make the sex crap. Being "good" at sex is partly having a basic knowledge of biology, experience, and knowing that the first time WITH someone new might potentially be crap... not just your first time. Your first time with someone ought to be about having fun, communicating, enjoying and discovering each others bodies... if one or both of you doesn't have an orgasm, thats OK. If one of you has one too quickly, thats also OK.
If you communicate honestly, and don't have any huge expectations, it will be far better than lying about it, trust me. Just tell her the truth. Being a virgin is nothing to be ashamed of.