"The vagina can stretch a mile before it will tear an inch."

I heard that from somewhere but cant remember where.

Just go with it dude. Its your first time, so you aren't even going to know exactly what the hell you're really doing so it will come naturally slow. Just dont start humping like a wild dog or anything and she'll be fine - and stick to missionary style first few times. then later experiment with other possitions. First time should ALWAYS be missionary with a new partner - and in your case, virgins.

Other than that I dont know what to tell you - I never been with a virgin.