Should I go back to my best friends? HELP?

Yesterday, me and this boy were making fun of my best mate (for a joke), but then it turned serious and now I keep saying sorry. But she won't accept my apology. So at break, I went to hang out with some other girls in my grade. (And they use to be people me and my best friend would make fun of) and now I think I'm becoming good friends with them. I don't know if I should just go back to my best friend? Because all my other best mates hang with her, but I'm making new friends. We have been best mates for 10 years now and she is in all my classes and we are doing a project together. But the thing is, throughout us being best friends there are the occaasional things that get annoyed at about her... So what should I do? (Sorry if this is confusing)