Messaging a girl I like?

[Chris]

So there is this girl that I like. I only have her in one class, gym. I have never really talked to her before. The biggest issue is that she is very popular, and me, not so much. It's really hard to talk to her in person because she is always with a huge group of friends, and as I stated, I only have her in one class. Do you think that sending her a Facebook message along the lines of "Why hello there!" Or just a simple "Hello!" or something is acceptable? If not, then what other ideas do you have?