Yes, George may have made the movies up as he went along, but there are no holes in his story....
"Your father should have stayed here and not gotten involed" - Maybe he was refreing to young Anakin leaving Tatooine with Qui-gon and Obi-wan the first time round...
After all, Shmi spent a good few years with the Lars, plenty of time for her to tell the story of how her little boy was going to be a great Jedi!!!