Whatever you do please don't quit your firefighting job if you can reasonably accomplish your flying goals and still keep it. I was in a similar situation as you are with a similar paying job - railroad conductor. I however couldn't do both as I didn't get enough time off. If I could have, boy would it have mitigated the risk. Plus if it turns out you don't like being an airline pilot as much, you have your firefighting career. And actually at Frontier we have guys who are BOTH! Full time! Course I think they are very senior.