My oldest was probably 6-7 when I took him out. Around 5 for fishing. Same with my youngest. The oldest is 13 now, so there’s that….
My youngest is now 9 and he loves going out with me. Even better when we get to see deer or get to take one!
my advice is to do short sits close to last light. If you attempt longer sits early on, they get bored wicked fast. My youngest can now last 2-2.5 hours, more than that is still pushing it, especially if it’s a slow.