Is Quitting Your Job to Join a Band at 35 the Best or Worst Idea Ever?
Before you start tweaking either side of your life, you need to get to the marrow, because this is big and you cannot be lying to yourself about it or upselling your motivations to the people in your life. (Hash it out on paper if need be, but do not over-burden your woman with this; she needn't be the one trying to talk you into or out of it.)
You need to reach out to someone who is in a position to tell you what the greener grass is like. I'm tasking you with talking to a handful (say three or four) of people who are older than you who do music as their job. Ask them what it's really like. One of them needs to be someone with a family and a mortgage--someone with a spectrum of real world responsibilities--not just 50-year-old bachelors who play in blues bands, and not people who are in bands as a way to continue a high-functioning stoner lifestyle. Famous people do not count either.
Things to ask them: How do they do it? Are they happy? Are they having to give lessons on the side? Would they do it again? What would happen if their band broke up? How lean are the lean times? Take them out for a Shirley Temple and play 20 questions. Mull their answers and get all Ghost of Christmas Yet to Come in your mind--do you want their life? Once you pass 30, you have no excuse for making uninformed decisions.
You are unmarried, don't have kids to feed and you live in a Southern college town--you can probably get by on not very much. Judging solely by your girlfriend's online trail journal/pictures of her goats (I Googled her, duh), she is an awesome, free-spirited, can-do gal that loves you (on Instragram at least) so perhaps she is down to take that ride with you as you follow your muse. Maybe you can sweeten the deal by feeding her goats when she is at work. It sounds like you are in a good life position to jump back into it.
Just keep in mind you are not 22, so just make sure you really have the energy to do it and the temerity to potentially significant downgrade your lifestyle. Don't rule out having some little jobby-job so that you are not mooching off your lady (or anyone) and can take her to the movies or buy her some $22 hiking socks just 'cause. You are no less pure an artist because your part-time gig is what keeps you afloat.