CONFUSED!!! Please HELP!!! Don't know what to do!!!?

I KNOW THAT THIS IS LONG BUT PLEASE READ EVERYTHING SO YOU CAN KNOW ALL THE DETAIL! :)

Well...during the summer, I made some new friends and I found out that they are going to the same high school as me. I was really happy about that because I'm about to start 9th grade and I don't know anyone at the high school I'm starting because I was supposed to go to another one but I auditioned for a Fine Arts Magnet Program with guitar that they have at the new school and made it so no one from my middle school is going there. Me and my new friends already made plans for sitting together at lunch and I found out that they are the "popular" there. Well, about two days ago I met one of my old friends that I went to 6th and 7th grade with (I went to a diiferent school for 8th) and it turns out that she's going to the Magnet School too. But the problem is there is a new girl that I don't know and since I wasn't with them during 8th grade, a lot of stuuf happenend that I don't know about. What I'm confused about is should I hang out with them or with the "popular" kids cause my older friends are kind of wierd but that's what I like about them and I'm not sure that my new friends are going to like them. But I also don't want to feel like the third wheel with them becuase they kept talking about stuff that happened in 8th grade. Please help!!! I really like both my old and new friends and I don't want to have to pick but I'm pretty sure that if I tried to introduce them to each other, their not going to get along. I am so confused right now.