I really don't see what is so hard to believe.
A 14 year old kid with a .22 is pretty normal stuff and most kids that age think they are ready to take on the world. I was a lot younger than that the first time I pointed a gun at a man. I actually had forgotten all about it until my dad brough it up a number of years back. Probably forgot about it due to my young age.
My dad took me with him while he sighted in some hunting rifles. We went to part of a ranch that he knew the owner of and had permission to shoot on. While he was doing that a truck came driving up very quickly. There was a lady in the passenger seat and a "cowboy" that got out. He had one of those belt buckle revolvers and pulled it on my dad, pointing it at him, while yelling at him. He was telling him something about trespassing and something else. My dad, had set the rifle he had been shooting on the ground.
While this was happening, I walked around and picked up a rifle off the hood and worked my way around to one side, so my dad was not directly behind the guy. I could not pick the gun all the way up to my shoulder, but I held it, pointed at the guys back.
Finally my dad interrupted the guy. He told him something along the lines (and I don't recall exactly as my dad describes it, except for the phrase he used) of "We have permission to be here and you can go check, but if you don't stop waving that gun in my face, my son is going to blow your F-ing heart out of your chest" and then he pointed at me.
At this point the guy said he was calling the Sheriff and we were going to jail. My dad ended up sighting in his rifles. No Sheriff or deputies ever showed up.
I did not remember anything about the incident until my dad brough it up probably 10+ years ago now. I do know I was younger than 14 by a good ways.
So the story of a 14 year old kid taking pot shots at attacking aircraft with his .22 is not very hard to fathom at all. Heck WWII had a lot of instances of teenaged Partisans, with some as young as 14.
https://www.history.com/news/dutch-resistance-teenager-killed-nazis-freddie-oversteegen