Can I use a hair straightener to make my hair like zack efron or justin bieber?

Um... you could try it, but it looks a bit short and sticks straight up because there's no weight on it. I'd say buy some gel and try to mold it in a way kind of like that, but you definitely need to grow it out. Go ahead and try, though? No harm, no foul. You're pretty likely, with how short it is, to burn yourself and not be able to get the straightener around it. It shouldn't take too long to grow, though, so if you really want to try it talk to your stylist about it and they'll give you a good idea of how long and how to style it properly so you don't look ridiculous. Not that Justin Bieber doesn't look ridiculous with his "I-try-too-hard" style. Good luck :) Don't burn your face. Then you'll really look silly :P