Why dont i get girls?

Ight im 15 ive had 2 gf one not serious at all the other some what. Never had a steady longest is 3 months. Seems like i should definatley have one im goodlooking athletic and smart but thats not even waht i find the best. i see these other kids getting *** all the time that are total beatoffs. wtf im a nice guy never hurt a girl physical or emotional millions of times complemented on my looks whats the deal? and ive been with numerous hot goodlookin chicks but right before we kiss they hookup with someone older or someotehr kid. ahhh i need a gf..please what am i doing wrong and if u say im y not at all very shy modest kid, in fact was afraid to make eyecontact wth the hotties