You in high school, you shouldn't be watching Tim's Flawless Natural!
Well ok ok I've seen it, and Transformations, and The Blueprint... But do as I say not as I do, right.
Your falling into the trap of overanalysing. Really people shouldn't be asking questions about stuff like this. But ok if you know what your doing and you STILL legitimately want to know, thats ok.
It's fine. Try it. Use your own experiance to find out. Everyone reccomends high fives and girls can even get weirded out by that, at least at first untill they see that you are cool with it. It wont weird the girl out unless you feel weird doing it. Handshakes are a great way to get kino in early, for girls it's more like a hand hold then an actual shake.
Crazy handshakes that you make up are fun and a good tool as well.