Why do the good girls have hard times?

i'm a very attractive girl 15 year old girl (if i sound conceited I don't care) i'm very confident, I don't dress like a skank, friendly, and i have high self esteem. yet i can't seem to find anyone interested in me. The only people that seem to say things to me are 12 year old boys, perverts, and street thugs. Yet girls who are evil or seem promiscuous have boys slobbering at their feet. How does this even work? I don't understand.