I started a thread some time ago on the subject of opening a new club. You can go to that thread by clicking:
Lots of folks wrote in with advice. Now, that said, I've been training twenty years and teaching for close to eight, and this dojo is limping along at best, so at age 15 you might have an even harder time. I think it's really hard to start something from scratch, but it is really worth the effort. I am very happy that I've done this, but it is still extremely difficult, and I'm still having a hard time getting folks in the door.