Is this guy romantically interested in me?

Of course this is one of those “oh she’s online trying to figure out if he actually likes her” situations. Yes, I’ve researched body language and behavior, browsed through WikiHow, and read through some generic “does he like you?” quizzes that require an email at the end (I didn’t get the results because I can’t be bothered with the process).
I’m resorting to yahoo answers because I just need some input and various opinions.
We are both in college, around 20 years old. He’s in one of my work groups here. I have been interested since the first time we’ve actually met, but I’m not sure it’s the same for him. We always look at each other when the teaching assistant explains things to our group, then smile and laugh/giggle silently every time we make eye contact. Another one of my group members said that every time we laugh she thinks it’s about her, but it’s not. (She’s a good friend, too, so no harsh feelings there). He’s generally quiet, so maybe shy? I know not everyone who is quiet is shy... But recently he has been kind of standing closer and looking at me more (maybe just my imagination?). I’ve noticed him fix his hair, but a lot of guys do that without trying to flirt or seem interested. I don’t see him often, maybe 1-2 times a week depending on the project...

If you have any opinions or advice, please let me know. I’ve been acting friendly with him, maybe a little flirty without being too crazy.
Thanks in advance!