Well, for all I know, Anna's still at home, and she's ruling Arendelle in my stead, and I know that she is doing a magnificent job of it.
I used to pretend that my parents were only on an extended trip, and so I had to be able to show them that I had learned as much as possible while they were away. And even after my coronation, some part of me refused to believe that they were really gone. No one had found their bodies, let alone the wreckage of the ship.