Don't know how to act around friend who likes me?

[Bellatrix Lestrange Suspended]

I just found out that one of my friends, well acquaintance, has a crush on me! I'm more surprised at the fact that HE has a crush on ME. He's popular, funny, and smart...and I'm average. People say I'm intimidating, scary, and a little dismissive but funny when you get to know me. The thing is, we've never had a lot of conversations between each other. We share some hi, how're you's but nothing like a full blown out conversation. On twitter, he replies to most of my tweets. He told me I was inspirational and a genius.

Also, the girls that are all over him are SO PRETTY. Their skin is like porcelain and they have good bodies and I have an okay body and a face that could be better. I also don't dress up everyday. Some days, I'll wear my baggiest sweatpants but he's still attracted to me? How? I definitely don't go around with my boobs out and I'm only comfortable talking around people I know....

Now when he makes conversation via twitter, I usually favorite his tweets when I don't know what to say. I like him too the only thing that's holding me back is being judged. Like people going "ew why are you going out with her? she's ugly, she doesn't dress nice, you could do so much better" because people do that a lot in my school.