My advice would be go for it. Last year I was 22, a virgin with exactly the same issue regarding confidence and chatting up girls. I had a punt and though I sucked the first time, it was a big burden off my shoulders, and you definitely improve on your second and third punt till it is second nature. However, be careful it can be addictive, as you realize there is this whole other world that you never knew about. Good luck and if you go through with it with that girl (looks a stunner) leave a review and let us know how you got on. Ps other posters are right- agency girls generally look better in the photos than in the flesh, but an agency of that standard should be providing girls who look very similar if not identical to their photos.