Don't know why, I didn't remember this before. My dad was right handad, but he shot left handed. For someone who didn't shoot much and wasn't even very interested, he was an excellent shot with both rifle and shotgun. So he was obviously was left eye dominant and for some reason had the good fortune to learn to shoot backwards. His family were mostly avid shooters, so maybe one of his brothers straightened him out at an early age, but I doubt that people knew much about eye dominance in the early 1900s.
At any rate he learned to shoot backwards, and I'm sure the younger you start the easier it is, but you're still a spring chicken lefty.