Should I get highlights?

I have dark brown hair and for a while I have been wanting to get dirty blonde highlights. I am almost 13- some of the girls in my grade just got the same highlights so I don't want to seem like a follower even though ever since I was like 8 I wanted them. But I still don't know if I should. What do u think? Would dirty blonde look good? What brand should I buy? Or should I go to a hair salon? How much does it cost? How long will it last? Please help me even if you know he slightest bit of info or the answers to any of my questions thanks!!!!!!!!!