As a Finnish person, I laugh in the face of the idea of someone being too young for sauna.
In fact, go back some decades (but less than a century) and most childbirths were done in sauna. You can't really get much younger than that. Well, the sauna usually wasn't heated for such occasions, but still...
Oh my.Aren't kids a little too young for something like a sauna?She saw me...Whoops!Bare-face