Your late 30's is not the time to start chasing your pool dream. I'm a few years younger than you and I can't even fathom at this stage in my life having a net worth of a few hundred bucks and wondering what I was going to do on a day to day basis....and hoping to scrape a few bucks together on the local pool tournament trail. That sounds like an absolute nightmare to me.
Here is my unsolicited advice for future success.
1. Go find the best job that you qualify for. If it isn't your dream job right away, don't worry...they say the best time to start looking for your "next" job is when you start your current job. And I don't advise working in the pool room. That would suck working where you wanted to be playing/hanging out. Separate the two. Find a job with the best benefits you can find.
2. When you're grinding away at this new job and feeling discouraged sometimes because, yes, sometimes working is boring, and you have managers that are jerks, and it isn't your "dream" of being in the tournament spotlight, think about the benefit of being able to support yourself, contribute to society at large, and not being a burden to others.
3. Don't do drugs. None.
4. Don't over-indulge in alcohol.
5. Start investing 10% minimum of every check into a 401K. Before doing anything else pay yourself first. Some companies will match you up to 10%. That is free money towards your retirement.
Follow this advice and in a few years you'll have a nice little apartment (maybe you'll have purchased your own house, where you could put a pool table), a little money in the bank, your own car, and you can play all of the pool you want in your spare time.
Anyhow - good luck.