Kids Account (Nintendo)?

I have a question to all those who are familiar with Nintendo Account (Switch) when creating a child account for his son / daughter that if my child is of age to normal Nintendo account or my child has to create a new account. I have found nothing in their help

Looking forward to your replies

Oh that's a very special question.

If I were you, I would try to contact Nintendo Customer Service directly with a message or email:

https://www.nintendo.at/Hilfe/Kundenservice-11593.html

I can hardly imagine that anyone else knows. : /