To stay more "in topic": don't forget that sometimes it IS important to have some kind of a fallback plan. The sad truth is that, there are much more people dreaming of a career in the music business (playing or building) than there are people actually making a living out of it.
When I was in high school, I didn't have any interests besides music (well besides chicks and beer), but as you meet new people, get some summer jobs, go to college, you'll probably discover a lot of other things that will pick your curiosity. The problem is that, high school is the period where we have to make some of the most important decisions of our lives, but we're not necessarily ready for it.
However, I'm happy I didn't decide to do music full time, because now I have a steady income which pays the mortgage and feeds the kid, yet I still play out once in a while, write some songs. It is true that my music suffer compared to when I was younger, because I don't have as much free time as before, but on the other hand I still have fun doing it because I don't have any stress, any pressure, cause it's only a hobby, I don't have to rely on it. The money I make out of it is pure candy for me. Sure I don't like my job as much as I like music, and I never though I'd end up in this field, but I like my job because it allows me to keep playing and because, well, it's not that bad.
As for being a luthier, you have to added advantage that those skills can serve for other purposes, like cabinet making, or working in the construction industry. If you develop those skills, you can make interesting money working in related fields, and then maybe someday start a guitar store where you can offer your service to repair, modify or build guitars.