Too young to really appreciate anything. No eye protection either. I would say 5 or 6 would be the youngest, at this point it would be the same as if I took a video of my dog holding the gun while i shot it.
Besides, I believe that if kids are exposed to guns, taught to shoot early, and taught that its ok to handle guns as long as dad (or mom, if that may be the case) is supervising, they won't see guns as this great forbidden fruit and will be far less likely to play with a gun if they come across one.
No eye protection!
- I doubt the ear protection was designed to be used/work on someone that small, but I may be wrong.