Keep the salary and pay down your debt first. That's one less thing for you to worry about when you start a quilting business. That isn't what you want to hear, but it is what you need to do - unless you are going bonkers on the job OR would get a nice pension if you retired now.
Assuming that you can dedicate a reasonable portion of your salary to paying the bills now, start cutting personal spending now. Try to pay the bills off faster and save some money. This is good preparation for when you START the business - your income will be lower so your 'out-go' has to be lower, too.
I can't give you any info about starting a quilting business. I do know that machine quilting is a lot of work and takes time - and all I do is edge to edge quilting on personal quilts. I think if it was my business, I would get tired of it extremely fast. Quitting your job COMMITS YOU to quilting full time, so think long and hard before you quit.
i wish you luck. Decisions like this are never easy.