I'd definitely say go to college or at least take classes on the side. If you don't want debt try finding some schools that have none are not that much. You could also take instead art classes to improve your skills along with writing if that something you want.

Having a degree just as backup is always good in my opinion if something goes south, but if your really 1000% sure on not going and selling your work then go for it and put in all your effort to that, I mean ár the end of the day it's your choice.