Everytime i see a girl i like

Everytime i see a girl i like, i get really shy and i don't talk to them i actually stay away from them or if i'm with friends i just keep talking to them and i don't even try to talk to her i can't controll it, i really missed out on really go chances in my life because of my shyness, i'm 15 and i've never had a girl before of a frist kiss, And don't tell me "wait i'm still young it will Come when the time is ready". what if i dosan't cause i don't talk to any girls i only have guy friends, everytime i try to talk to a girl i like my hearts just start racing off like am runing a race, And i run out of things to say and i ge really insecure, i don't know what's my problem, in middle school when a girl tells me she lided me or show me sighs i just neglet her, and now i feel alone cause i feel like all my chances i had is gone, on the weekends i stay at home on my computor, i can make friends with gys very easy but when it cames to making friends with girls i just can't, sometimes i wonder if i'm gay and i feel like am never going to find love.