@trecocl,
You are not pathetic. I have a 15 year old daughter - and almost everyone at that age feels similar to you. A guy is never going like me, etc. I hear it from her and I've heard it from her friends. The girls you mention that have had "boyfriends" at 12 - they are the ones that are really different. And believe me in the long run you do not want to be like them.
If you are really feeling down on yourself - could you talk with a counselor at school? I am being honest here -my daughter had an issue in the past school year - it was so bad she was begging for me to have her home-schooled. I had to drag her to school almost literally she missed her carpool because of crying. So I brought her out for a specialty coffee and then brought her in school late. As we walked in I asked the principal since he was there if there were someone we could talk with. He sat us down and she explained how she was feeling - he brought us to their adjustments counselor and we talked it out. She was given a pass where if she felt stressed to she go there and de-compress.
Long story short she is feeling much better - I don't know if this is something that might make you feel better but sometimes talking to a non-judgemental person that understands how high school be can help.
In any case, I think you should approach this boy as trying to be friends. Say Hi as jespah said. Then maybe ask about some sort of homework, or maybe that teacher is really pain in the butt huh? Just some passing comment or something that feels safe to discuss.
don't worry about him not liking you or not - if he is that judgmental that just looking at you he wants nothing to do with you - then he isn't a nice guy anyway. Or maybe he feels just the way you do - like he doesn't belong and a friend might be nice.