I agree, start off small. Why not use your Facebook situation as a reason to meet her. Obviously it makes you nervous when she is with friends so wait until you see her alone and say something like , I think I just recently saw your pic on Facebook. Is your name ??? whatever. I think its a good idea but my approach may need some tweeking. You don't want to go through another summer kicking yourself you never approached her. Also if you wait too long she may end up not being single anymore, especially if she's as pretty as you say she is. Not trying to add pressure but I think you should say hi. Bump into her and spill your coffee. Hopefully on yourself and not her but if its her you can offer to pay for the dry cleaning, or whatever. I hope you attempt to meet her!