That same kid may very well be dressing and dragging a deer for his father/mother/mentor years later when they have bad knees or back. When a kid is mature enough is really something only a parent can know. My friends daughter will finally be old enough to hunt here (NY) this year at 14 and she's been mature enough for years. My ex shot her first deer last season, I field dressed it and had no problem doing so. She also was a huge help tracking my poorly hit archery buck earlier in the season. She actually found it (what was left by the damn coyotes anyway) after 600yd tough tracking job.

Being a part of someones first deer is the best experience you can have deer hunting.