In my academy in CA we had people in their 40's! They did very well considering and one wasn't exactly in the best shape. If you have a "feeling" I would say do it. It is the funnest job in the world! It is never the same everyday and can go from doing nothing to adrenaline paced chases or fights in less than a second! I don't believe you get thanked in any job, people just don't believe in thanking and telling someone they are doing a good job anymore. I was a physical therapist before an LEO and I didn't get thanked at all in the medical field. It was boring, same thing everyday work, which is why I switched careers. I found myself waking up and not wanting to go to work. Not a way of life for me!
You also have a lot of freedom out there (which attracted me) and bosses hardly ever check on you unless you have an A$$ for a sargent. Most are really cool and will back you up if they have to. I would suggest the sheriff's department as you will tend to promote faster than a police dept. although the pay is higher to start off with in a police dept. I don't agree that you get paid very little, one of the agencies I know of in So. CA are starting at $76K a year, not including overtime! Not bad! Most are between $30K and $60K starting pay. I am starting at $45K, not including overtime. Not bad either! I get raises every 6 months! I know Lt's and Sgts. making in the 6 figures a year! Afterall, its not the pay anyway, for me its having a job that I love to do, one that I can't wait to go do. No amount of money can replace that feeling.
My dept. made it mandatory that persons 35 and over have a treadmill test for heart reasons, I believe. If you are in decent shape you should have no problem. In my academy we ran about 6-8 miles a day, three times a week.
As for working weekends and holidays...once you get some seniority you will have better hours, but you have to put in the time first, just like the military, which you are used to.
Gunslinger, dinosaur, and poacher has some valid points too.
I feel as a Cop you are the center of attention. If you go to a party or some social gathering and people ask you what you do, they tend to gather around you and and want to hear some of your stories. They ask a lot of questions as well. Its pretty cool. I don't know of another job where people react that way to you. Of course there are some negative reactions as well, but those people are usually ignorant, liberals anyway! haha
There is also the comraderie (sp) of other LEO's. Its like a family relationship wherever you go.
USP45, its all in the perspective of the individual. Every job has its plus's and minus'. Its all in your attitude. If you are one that complains all the time, or can't seem to make the best of a situation or if you are one that likes the same thing everyday, this is not a job for you. However, if you like constant changes, seeing something different everyday, enjoy outdoor work, and people (if that's what you want to call them), then you will like this job. I say do it, man, we always need a good man, especially a pro gun man!
Integrity is the cornerstone to law enforcement! Good luck and keep us informed on your decision.