Elisa from Rae Carson's The Girl of Fire and Thorns Trilogy definitely has this moment. Born with a magical Godstone that indicates her vitality, Elisa has always felt like a disappointment next to her sister and constantly eats her feelings. When she's taken in marriage, becomes queen, and is then kidnapped and marched across the desert, that's something that, at first, she feels ill-equipped to handle.
Cinderella: A character who transforms
In Tahereh Mafi's Shatter Me Trilogy, Juliet has to learn to love and forgive herself for the superpower she possesses, which kills those she touches. She also, over time, learns to embrace the power and use it in her fight to make her dystopian world better. It's a transformation of confidence, and it feels like classic Cinderella to me.