Hey, whats up guys

I just have quick question. So I'm in high school (18 m) and I'll pick up a girl there maybe once in a blue moon, not that often at all so today I thought I'd test my luck with a girl that I think is pretty cute(HS are not really that mature so that's why I say "luck"). I approached and opened perfectly, but it didn't go right, she just kinda looked at me and walked away with her friends before I could even introduce myself. This didn't bother me too much because I don't really care that much she's just another girl,but I'm more curious about how the interaction would of went. Would I have gotten a number? A smack in the face? An Instant date to the cafe? My question is should I give it another shot and maybe try to catch her without her friends around? and how would I re- open " Hey I didn't catch your name before you rudely walked away" haha. Just curious on your thoughts, thanks ;)