How were Maggie and dee different as children? Is the difference important to the story?

Mama recalls the fire that burned their first house down. Maggie still bears the scars of that fateful night. Mama also recalls that Dee just stood there and watched the house burn with a condescending smile on her face. To Dee, the old house defined them as poor black farmers, the descendants of sharecroppers. Mama remembers how Dee willed herself to be different from her rural neighbors with her book smarts and by having a style all her own. Dee wanted nice things and was intent on getting them. If she couldn't afford to buy fancy clothes, she would make them. She seldom heard the word "no". Maggie conformed to what was expected of her. Unlike Dee, she is timid and shy. This dichotomy between Dee and Maggie will be intensified when Dee comes to visit.