It’s always felt much more Fantasy to me. It takes place in a world far superior to ours technologically, but it’s still magic, wizards, and a princess. It’s more Tolkien than Asimov.
Science fiction, to me anyway, is where the science and technology play a major part of the story as opposed to just being the setting: 2001: A Space Odyssey, Planet of the Apes, Lost In Space, Battlestar Galactica, Star Trek.