Yes, retellings are slowly becoming their own genre. In most cases, they're fantasies or a modern retelling of a classic. I do get why you're a bit hesitant as magical retelling does sound a bit . . . amateurish. Not saying it is, but I do again understand your reasoning. I recommend the following to ease your worries: TITLE is an XX,000-word fantasy novel and retelling of Austen's PRIDE AND PREJUDICE.
Keep it simple and to the point.