As someone who has moved 22 times in the last 28 years.... I know what it's like.
Best thing I can recommend is to look for a job somewhere where the people are young and likely to be people you want to hang around.
Try a shop that is a ski shop in the winter. Or if you are with in a few miles of a ski area, see if they need someone in rentals for bike or golf or whatever.
There may be a cool restaurant you could be a host at.
I went with an amusement park when I was 15. The work wasn't that great but we all had so much fun hanging out that it was no big deal.
Another thing... since you are 15, have you done drivers ed yet? My drivers ed class was a lot of fun and really neat cause I got to know people outside of my middle school before going into highschool (which started in 10th grade).
Another option... reach out to NS. It's pretty likely that someone on here is in or near your town (unless it's in alabama). I have met one of my best friends because of NS. Moved to Summit county, knew no one, reached out, had insta friends. If you're a decent person, people don't mind playing tour guide.
Finally, if you aren't athiest or hostile towards religious people. Check out some of the local youth groups. I actually am atheist, but one of the churches here has a music class/group where it's just about hanging out, playing guitar and learning some music theory. They know I'm athiest and are pretty cool with it. Their reason is more so just to show they aren't jesus freaks and that it can be a welcoming environment. Besides, religious people often have non zealot friends as well. So if not the church group type, check on what non religion related groups they also offer.