Hey Bam Bam,

I'm finally at a real keyboard, so I'll take a stab your questions.

First off, plenty of guys/gals have made a mid-thirties career change into aviation. It's not uncommon. Flying is one of those rare jobs that people always want to do and eventually they decide to go for it. Unlike, say, plumbing. The biggest hurdle most people face is timing. There are good times to get into aviation, and times when it's near impossible. Right now, fortunately for you, we are in one of the better times.

That's great you already have your PPL. Flying for a job, however, is nothing like that. It can be, but it is usually not. Really, this will largely depend on your personality and how resistant to constant negativity you are (from both your peers and your management).

Your age will not close any doors at this point. Some people may like your varied back round. Right now, if you completely all the rest of your training in say, 12-18 months, and instructed as best as possible, you could meet the required regional mins in 2-3 years. You'd still be under 40 with 25+ years to fly.

It is not challenging to get a CFI position. Especially if you go through a school like AllATPs or a few others that essentially give you a CFI job upon completion of their curriculum. Besides CFI, there are other positions that you can look for as well. Some will require more hours than others.

If I were you (and I am currently mid-30's btw), I would MAKE SURE I had plenty of money saved up and that I really did truly hate my current career. It's a huge gamble. I'm a bit of a flip flopper myself, so I need to be positive, for at least six months. I'd also take inventory of my "Where do I want to be in five - 10 years."
You will not be making much money, almost none to your retirement, and starting a relationship under these circumstances can be difficult. Further, when you do get that regional job, you are likely to work weekends, holidays and be on call. You will not have a normal schedule, and it's hard to meet people like this. You can, of course, it's just not as easy as a normal job in my opinion. Your work friends at the airline will likely live all over the country... can't exactly stop by after work for a beer.

If you're committed I would look at all of the accelerated courses available to you. Consider their completion rates, whether they will give you a CFI job, if they have connections to regional airline partners, the total cost, payment plans, where they are located, how you will live in said place etc. Come away from this with as little debt as possible. The industry can change in an instant and you don't want to be saddled with $80k in debt and no job.

Start volunteering. Start trying to achieve anything you can at work. Any accolade you can get, get it. Write everything down in a notebook so you don't forget it. You'll need to remember it later.

Good luck.