I think that abstinence, and waiting 'till marriage is way overrated.  Dude, you're in your early twenty's with a chick you've been with for two years, you are as ready as your ever gonna be.  I know the first time can be a little nerve racking, and you probably want it to be speacial or something, but once you get comfortable being naked in front of her your sex life will jump to a whole nother level, and by then your 'first time' won't mean squat.  You should grow a sack and go for it.  She probably wants it more than you.  But hey, thats a typical response from a typical amoral 20 year old.  Just my 

  opinion