you are doing the right thing keeping the firearm from being this mysterious object and promoting saftey and right from wrong. I did a similar thing with my nephew between the ages of 10 to 14 now that he is 17 he has lost interest (hopefully Temporary) but he knows what they are, what they can do and gun safety if he regains interest he knows the basics and knows he can come to me or other uncles for advise and just a fun day at the range.
"Firearms stand next in importance to the Constitution itself. They are the American people's liberty teeth and keystone under independence ... From the hour the Pilgrims landed, to the present day, events, occurrences, and tendencies prove that to insure peace, security and happiness, the rifle and pistol are equally indispensable . . . the very atmosphere of firearms everywhere restrains evil interference - they deserve a place of honor with all that is good" (George Washington)