Why are girls so shallow?

Alright, I'm a kid, 14 years old, and I'm not exactly the best looking kid. My hair is kinda, well not "ideal" for what girls like, or girls in my school (flippy, skateboarder), I'm short, I'm skinny, uh, acne. Well I'm a big flirt, but I've only had 2 girlfriends and I'm pretty sure they were out of pity. Girls that I like and tell them, tell me I'm nice (since I'm such a flirt) and funny (I'm the cl-clown type of kid), but nobody will really go out with me for now since I have such unappealing physical features. Well I try to stay in shape and I have a 6-pack and it's a legit 6-pack, not one of those nasty looking ones that sometimes happens with kids. Well I have a picture of me and my niece (who's sitting beside me) and I have no shirt on. I post this picture on facebook and every girl is now telling me how hot I am...shocker...So girls, why are some of you (the majority) so shallow. I know most of the answers will be "I don't care about appearance, it's the personality", but I don't want to hear that, girls at my school want the "hot" guys.