We played with army men in a similar way. In my case they were soft plastic dudes about 1/30 scale (give or take) and we'd arrange them in positions among plants and dirt, then my buddy and I took turns shooting them with BB-guns.

But for model making I remember the 1st one I built, I do not remember how old I was or what year, but I got sick while visiting grandma's house one summer. She bought me an FW190 (pretty sure it was Revell/Monogram 1/48) to keep me entertained (and quiet probably), and I made a godawful mess of it. My best estimate would be 1970-1972 based on where I lived at the time.