Seon is in Kanton Aargau. The nearest towns are Lenzburg and Aarau.
HTH
Here's a link to the sauna I go to in Seon. The entry is Fr 13 and includes use of the indoor swimming pool as well.
I have taken my kids 8 & 5 into the sauna at my health club, and nobody bats an eyelid. Wouldn't worry if I were you