First off, sorry for long post guys, just needs some background info explaining.

First year at uni, I knew this girl through a mutual friend (the mutual friend was in my halls). During freshers week I added both the mutual friend, and this girl. I then saw the girl maybe 5 times over the coruse of first year, and every time she was with the mutual friend and we just said "hi". I never had more than a one-word conversation with her. Let me point out that at this point, I wasn't too fussed about this girl anyway. Didn't really find her attractive.

So in second year I didn't live with the mutual friend anymore, so I've not seen this girl for a year and a half (I'm now nearly finishing my 3rd year). I've still got her on facebook from freshers week, but we've never interacted on there (nothing at all, no facebook chat, no liking photos or commenting on each others wall etc., I don't really use facebook to be honest other than to stay in touch with mates from back home).

So anyway...I bumped into the girl today in the library. MUCH more attractive than I remembered her! We got chatting, and it went pretty well. Bit of teasing, laughing etc. Basically, a good little bit of light flirting and joking around. Unfortunately, I'll hold my hands up here - failed to close, no number, or anything more! I'm not looking for tips so much on closing - I have done it plenty of times in the past, and whilst I'm by no means an expert, I normally have decent-ish success. Today, for some reason, I just failed to go through the motions.

The question is this then; given that I've got her on facebook from the first year, do i speak to her? Is it a bit stalkerish/creepy? Obviously we spoke today, so it's not totally out of the blue. Or do I just hope for a chance encounter.

The chance encounter isn't a bad idea - I mean I'm not that bothered about this girl. She was just pretty attractive, and seemed to have some potential, but if it doesn't happen, it doesn't happen. So maybe just leave it and make sure to close if I bump into her again.... on the other hand, we do already know each other slightly and there does seem to be potential for a fairly easy ride. So do I go for the facebook, or do I leave it? If facebook, how do you go about that?

Any help greatly appreciated guys!