Just added a girl I like on Facebook, now what?

[sc0oby]

There is this girl I like, finally decided to go for it and add her as a first step. We don't really know eachother, we never talked, we just know of eachother and that's about it. We hang out with the same group of friend's. I finally added her last night and she accepted it, the last time I saw her was on July 4th. It's weird because we never got properly introduced so that's why I have no idea on what to say to her. I want to message her something on Facebook but I have no clue on what to do or say. Any suggestions on how I could start up a conversation? Should I say something like "Hi (Her name) I don't think we ever got properly introduced to eachother so hope it wasn't weird when I added you. haha wasn't sure if you remembered me or not." Is that too weird? Any suggestions?