Why not? If the 17 years old knows fully well of the destructive power that the gun posseses by means of a bullet. Has that 17 year old been around firearms all his life , does he know how to safely use firearms? Do they understand that the gun is a tool and not a toy and when used improperly can and often will cause death or massive bodily injury? If the answer to those questions are yes (with proof of ability on a range) then I say yes that person can be armed.