Here are the facts

okay, I think this girl emily is staring at me, and I really like her, but I don't want to look like an idiot. there is a drawback to it, her best friend sits by me and there is another guy on the other side. does this mean she likes me, and how do I...

find out?

I think that you need to gently ask her.
What is the worst that can happen? She says no... but at least you'll know.
It may be scary to talk to her about it... but your going to have to get up the nerve and do it if you want anything to happen.

~Rose~

Be confident and take her aside by yourselves and ask her out. I mean if you do it without being all jittery and dorky then it won't be even remotely embarrassing if she says no or I'll think about it(usually means a no).