With the exception of the lead free primer target ammunition, the shelf life of ammunition stored under good conditions is so long that we mere humans don't have to worry about it. I doubt your young children will have to worry about. Even their grand children may not have to worry about it.
Smokeless powder samples from 1895 have not deteriorated yet. WWI era brass cartridges used to crack at the neck after a few years, but annealing has remedied that. Primers are sort of the weak link, the lead free primers are not good for long term storage. The old corrosive chlorate primers were the best, but even today's non-corrosive primers last a long, long time.
About 1979, I fired a .38 Spl cartridge found in my grandfather's desk. (He supposedly never owned a pistol, go figure!). It went bang on the first try, and I was surprised to see a big puff of white smoke. Yes!, it had been loaded with black powder, and was probably 75 years old at that point, (maybe less, maybe only 25).
I have fired some of my reloads over 35 years old, no problem. I have fired lots of 50 and 60 year old surplus ammo over the years.
Now, some times ammo is stored in bad conditions. Too much heat is bad, and oil vapor and fumes are bad. I have a few WWI era .45 ACP cartridges upstairs. I bet every one of them would fire. I saw a video where a guy tested some similar cartridges, and compared them to modern day production. Reliability of both was 100%. The old stuff some times had a barely perceptible hang fire. It was slightly lower velocity with a slightly higher standard deviation. The accuracy was slightly worse.
Still pretty good performance for some thing that old. Nothing to stand in front of.