Girls, good day, could you please tell me what age is suitable for taking…

Girls, good day, could you please tell me what age is suitable for taking children to the bath? Last year my daughter was 4 months old. We were in the steam room of our bathhouse and bathed her in a tub. This year I think it's worth considering a sauna on the lower shelf with a low temperature in the room ?. Mom says babies shouldn't be in there, maybe it can affect the vessels...