Your parents will decide.
You need to take this question up with the child's parents.
It all depends on the country and location where you live.
First of all you need to state where you live. The law is different, depending on the country where you live. Are you asking about metal BB's or airsoft BB's?
Not in the United States
you really need to be like 13 because no 1 will trust you. if your parents let you get a bb gun at age 10 and you shot some 1 then your parents are really dum..!
No.
Yes it is required.
We need to know the model number and condition to give an estimate
You need to Identify the make and model of the BB gun in order to get an answer not the serial number
21
Yes you do.
That all depends on the location, State or Country where the child lives