Depends on the kid, my youngest boy may be able to function without adult supervision when he's about 47 while my older one is one of those kids you have to remind to lighten up and actually be a kid.
Sounds like you have have a good responsible kid, one idea may be to set some parameters such as ground blind or shooting houses only, etc. I would be more worried about my kid's making a dumb decision of trying to hunt a tripod in high winds or something that I would be in unsafe gun handling.
