I was a CFI at a pretty good sized FBO (about 25 CFIs) and we had some older guys who would instruct part time... IE one or two nights during the week but mostly on the weekends. These guys kept their day jobs and used instruction as a way to get paid for their flying hobby.
Unless you are really looking for a major life change I'd say this is the way to go. If you want to drop the day job and try to fly for a living then you need to make sure you can be ok with making less than 30,000 a year for a few years. I'm a young guy, but I've been in aviation for 10 years now and from what I've seen with guys in your shoes is that the ones that part time CFI seem the happiest with their flying jobs. I think its because they are home every night, being a CFI is the closest to a 9-5 job you can get in aviation, they get paid to fly, they usually don't fly enough to get burnt out.
On the other hand I've seen older guys come to the airlines. At 50 if you get your ratings fast you could probably get hired by a regional. These guys don't seem nearly as happy with their flying jobs than the part time CFI guys do. I've seen older guys come in and really struggle with new hire ground and sim training....I'm not saying all older guys struggle, but it does seem like a higher percentage, I think it has something to do with the fact you have sooooo much to learn in a short time, and most older guys haven't had to deal with that for years so they "forget how to study". The other thing that the older guys complain with is the schedule and being away from home... You're wifey has gotten use to you being home all these years and now your in hotels and crashpads more often than you're at home...which seems like a good chance that AIDS (Airline Induced Divorce Syndrome) might pop up. And with the regionals you fly so much that you will get burnt out at some point....usually within a year. Oh yeah and most first year F/Os make less than 30,000 a year.