Steve 'n Dallas -
LOL!
Based on personal experience, I can tell you that your story is a LOT closer to real life than one might think!
When I was in ROTC training at Ft. Bragg, N.C., summer of 1967, to become an Army officer, I remember that my training platoon, about
60 guys, was made up of all kinds of guys from all over.
But I certainly do recall that we really did break down pretty evenly into the "city guys" (like me) and, shall we call them, the "rural types."
Well, during things like PT (Physical Training, which, army style, is, let's say, a bit rugged), while we "city guys" were collapsing to our knees and gasping for air, the "rural types" were just standing there, doing fine, and eating it up.
Or during the mile run in full combat gear ("full load" they called it, and pretty heavy, too), guess which group would always come in first?
Toward the end of training we city dudes did start to close the gap a bit, but from the start it was very clear that the rigors of boot camp were just regular stuff to the boys who grew up in the wooded areas.
Your story also reminds me of a scene in the old film "Sergeant York" (1941) where, when on the firing range, York shows his army comrades just how well an ole country boy from backwoods Tennessee can handle a rifle:
https://www.bing.com/videos/search?q=seregeant+york+shooting+range+youtube&view=detail&mid=9b6e209a34bfa87bc2159b6e209a34bfa87bc215&form=vireBut as for your story, it was indeed pretty close to reality for me!