i am kinda in the same situation. ive been with my nonvirgin bf for 5 months (im a virgin) and we havent slept together.

i think the answer is when you both want to and feel ready... and that isnt as easy as im saying, i know... its hard to tell when youre ready.. and i personally dont know if i am..
but it depends on your beliefs and your ideas and stuff like that..

my advice is to talk to her about it and talk about what you want and desire and fear and have her tell you too...

remember, waiting is never a bad thing if you're not sure... there are a lot of relationships that aren't all about sex