How do you confront mean girls?

My entire life my mom has put me in small schools. There were mean kids here but I switched to a bigger school and the mean kids there are nothing like the mean kids at my old school. They are worse. This entire school year I’ve been really introverted, keeping to myself, and quiet not bothering anyone. I started dating this boy a few days ago and these girls in my science class who I’ve never talked to told him that he could do a lot better, that I’m emo, I’m too quiet, I’m not cute, and making fun of my style. I really don’t know what to do. Do I confront them? Or do I leave it alone? And if I do confront them what do I say? I’m really hurt.