How is Madame Losiel not a complely mature person at the end of the story?

Though she has let go of the dream, Mathilde still yearns to return, at least in her mind, to the night of the ball. She was for a moment what she always wanted to be. The yearning for this night tells us that Mathilde still had not fully matured from her ordeal,

But sometimes, when her husband was at the office, she sat down by the window and thought of that evening long ago, of the ball at which she had...