I am left handed, throw a ball left handed, eat left handed, need left handed golf clubs (only Crazy Golf you understand) and had terrible problems when my mum taught me to knit! Anyway, what I'm trying to say is that, once I picked up the guitar initially and was shown how to play a C, that was it, it never occurred to me to play a C any other way. Sometimes I think it would have been easier for me if I could pick with my left hand but I don't know for sure cos I've never tried and I don't intend to. I think people, especially children, just absorb what is shown to them and accept it for what it is.
I don't know if that helps but I hope so.