You can teach a 4~5 yo kid to clean up. Below that it probably comes down to personality/level of awareness, and it's probably a lost cause for 2 year olds and below.

Then you'll want an adult to deal with the body fluids and other nasty stuffs.

PS; what I mean by "teach a 4-5 yo kid" is really spending a lot of time with them rehearsing cleaning and drilling it down. It pays dividends, but you'll be spending months and months, if not years, doing the cleaning with them at a slower pace than if you did it just yourself.

Low cleanup time is even more important for kids doing it than grownups.