It’s really pretty marvelous. It’s full on fantasy—no urban or paranormal modifiers needed, no fairy tale retellings or alternate history to be seen. In fact, examined closely, there are tiny hints that this is a Pern sort of fantasy with a science fiction underpinning (this is a new world, one not meant for humans).
So, it’s straight up fantasy (aside from that tantalizing hint about the unknown backstory), but it avoids almost all the tropes: Elisa is not a spunky girl or a badass princess or a typical damsel in distress; she’s smart but lazy; destined for greatness but full of doubts—although also with enough backbone to push through them. She’s lousy at being a princess but she might just be an amazing queen, and the journey she takes from one pole to the other makes for some great reading. It’s also, from the characterization angle, difficult writing: a first person narrator, who needs to tell us all the ways she’s kind of a mess and all the ways she’s becoming fierce and fearsome, without become so telly that it becomes plodding and didactic is no small task to write.