How did Rapunzel realise that she was the lost princess?

More specifically, I don't entirely understand the scene back in the tower when Rapunzel sees all those sun symbols on the ceiling. My theory is that she decorated the ceiling herself, and designed it to include the sun symbol. She didn't know what the symbol was at the time, but during this scene realised that it was the symbol of Corona, and that she had first seen it as a baby. And then everything started to click together and she realised who she was.

Does anyone have any other thoughts on this? I always feel as though I am missing something in this scene.