22and never had a girl friend?

i know its really pathatic but i never had the guts to go up to a girl i lie and talk to them. I don't know how to rad pppl well and when girls were flirting i always thought they were being friendly and theres so many times the girl liked me but i didnt ask them so they just forgot about it. So how do i kow if their being frinedly or flity. i'm not a bad lookign person, i work out a lot so keep my self in shape, and I went to colege for a while but now joined the ai force