I don't work in the trade, so grain of salt and all that...
Going pro from hobby can be good and bad. I like programming, but do my own stuff a lot less since I started working in the field. On the other hand, I generally don't mind going to work. So like everything, it's a tradeoff. Just something to think about if your hobby is machining. You might want to have another idea for an outlet as you might be less interested in making chips after work.
As for age, consider how willing you are to learn new things and take a pay cut to start a new career. You're the only one who can answer that.
Are you good with computers? Professional machining seems to involve a LOT of CNC work these days. Being able to break things down into logical steps and tell the computer how to do it is the essence of programming, and CNC work is in many cases programming. It's getting better in programming, but ageism is still a thing there, much as I dislike it. I'm not sure if that translates to the CNC world or not, something to be aware of though.
I'm not sure what the outlook is for job prospects. It seems like this sort of thing has largely moved overseas, but I know the current government is trying to bring some of that back. And your local area makes a big difference. If you can find a local shop or two willing to chat with you, you might be able to get better information for the local job market.