Actual age of the pistol or the design? I have no qualms carrying a nice s&w revolver which design goes back to 1899
But as far as actual age i prefer to stay newer than 1960, due to cost of the gun, availability of easily swappable parts, and easier ability to source at least a near 1:1 replacement
I carry a Colt Model 1903 Pocket Hammerless .32acp that is over 100yrs old fairly often.
Just for giggles I have carried a percussion Colt .31cal Model 1849 Pocket model. The gun is a modern reproduction but it certainly works.
One a couple of occasions I have even carried a replica Paterson Colt .36.
If I had nothing else, then any pistol of any age, that I could get until I could get better. Of course, I'd only be confident if I knew it was in excellent working order.
Now, as for reality as opposed to a hypothetical situation: the oldest of my pistols that I carry and in which I am confident, is my Ortgies pistol in 7.65mm (.32 Auto). My confidence, might be a bit shaky carrying that one, not so much in the pistol or its age but rather in the ammo as I prefer a 380, 9mm or 45 over 32 Auto.
As for age, it was manufactured circa the early 1920's.
While in AZ, Prescott and Prescott Valley I felt at home seeing all the crotchety old bastards carrying various single actions in their cross draw BBQ holsters. It was the AZ of old where we all open carried.
I have carried this Colt Police Positive .32 S&W before and I didn't feel undergunned. It was made in 1917. I haven't shot it in a while. I probably should sell it and let someone else enjoy it for a while.