Should I ask him out?

Okay. So last year I asked this guy out to the junior prom. He said he couldn't because he already had a date to the senior prom, so I just let it slide and convinced myself he wasn't interested.

But now that senior year has started, he's been acting very strange. He refuses to make eye contact with me, I catch him staring at me on a regular basis, and he tends to become shy when I'm nearby (even though he's a very out going person). I can't tell if it's just because he feels awkward around me since I asked him out last year or what.

However, last year after I had asked him out and got rejected, we actually became pretty close and talked to each other often. Now this year he's completely ignoring me. Some of my friends think that he likes me now and just doesn't want to make the first move, but I made the first move last year and I really don't want to do it again (ESPECIALLY if I'm reading this the wrong way).

So my question is: Does it sound like he's even interested? And if so, should I ask him out or wait and see if he'll make a move?