Where you lived 20-30 years ago, etc. None of the kids I knew and played with as a child had a gun. I didn't have a gun, nor would I. Only one high-schooler that I attended school with ever showed me a gun, and it was a black-powder rifle that he put together from a kit, a replica from the Civil War. I even went to the range with him and shot that one.
My ex-fiance had a gun because he was trying to become a police officer. He went to training but was unable to ever get the hang of shooting. I was there with him, and they asked me to try for fun, and I actually shot his own gun with better precision than he did. But I never owned one.
I think it depended on where you lived. For example people in the country might be more likely to have guns. People in the heart of dangerous areas of the city might be more likely to have guns.
Owning a gun or having a gun tends to be bred out of the fear of one's surroundings, or the desire to engage in hunting or something similar. Fearful surroundings cause people to want to have means to protect themselves, hence more gun owners.
But it still isn't the reason for the problem. Granted, parents don't always lock their guns up properly, (my Ex-fiance had a gun box, with a lock plus a trigger lock on his gun), but that doesn't stop a determined kid from finding a weapon. The problem starts at home, when kids feel they have no one to talk to or no one to express their issues to. Sometimes the writing of the plans or the telling of the plans is as similar a cry for help as the suicide note.
We need to listen to those cries for help, because they can avert much larger disasters.
Brenda