I assume these places originated in Germany? (Lit. tran.: 'Child Garden')
I never attended a kindergarten - nowadays called a "pre-school" or "nursery-school" in the UK. I know no-one of my generation who did; I don't think they were at all common or even existed at all in our day (1950s-60s) anyway; but...
.... I'm not sure some adults I've known have managed to mature beyond that stage, except physically!