First of all, relax.
You're just saying hi. "Hi" thats it. People do it all the time. You need to get in the right mindframe- that is just be yourself. Forget everything. Forget everyone.
Just do it man. If you're confident, there's no way you can go wrong because people can feel if someone else is confident or self-concious.
And btw, I am a girl, and I have dozens of guys do that to me and no, it's never awkward. We always end up becoming friends within an hour. =)