Yes, you're absolutely right. That would be one solution, or at least a start. It's not normal that young adolescents can purchase compressed air guns. Also, police officers often find this type of weapon in the hands of street gang members, who use them precisely because they look like real firearms. As others have said before me, this confusion can also cause a police officer to shoot.
That being said, age should be a criterion. I would even say that I wouldn't be against making adults who use compressed air guns get a firearms licence. That would allow...