You can use the hashtag #asknostr for such questions as well 😉
I personally could think that Nostr can be used in a kids friendly way. I think as with most social media it could be a good thing to define some filters, to get rid of unappropriated notes in the feed.
And best work with an elevated WoT-score, to have only actively followed users in the feed.
But in general, I think nothing speaks against giving access to kids.
