There is no specfic age. Just make sure that if it is a child, he/she can handle the gun as if it was real. You must also be 18 to PURCHASE them, not to use them.
no
yes you can but be careful.
Your parents will decide.
21
It all depends on the law where you live.
18 to purchase
If its a BB Gun, Then Yes.
You need to take this question up with the child's parents.
18 years old
You must be 18 Years old to purchase one
Depends on your skills, size and parents.
No