I played around with my kid with supervision, and had her alone with ... midjourney, I think? Million weird dragons ensued.

I probably wouldn't give her access to chatgpt, but more for dislike of my kid's chats being stored with a corporation that will use it for something. That is the reason kid's email is protonmail and calendar is in nextcloud.

I would consider setting up https://ollama.ai/ ? You can run it locally and because it is smaller not as smart as state-of-art LLMs, it could train them better to be wary of the more advanced version.