How is contrast or descriptive language or dialogue used to develop the story "The Two Grandmothers" by Olive Senior?

One example of how the descriptive language in the story changes as the protagonist grows up is the treatment of her friend Pearlie.
Pearlie is the eldest daughter in a poor family that lives close to Grandma Del. At first, the writer is fascinated by Pearlie and her many skills. Pearlie teaches her to whistle, can balance a water jug on her head without spilling any, and is an expert at peeling green bananas. Pearlie's poverty doesn't seem to register with her, nor, for that matter, does the simplicity of Grandma Del's house, which lacks electricity.
As the writer grows up, however, she begins to detest the poverty of Grandma Del's place. She writes of Pearlie that she is "awful looking" and always begging her for clothes. She is so ashamed of Pearlie that she seldom goes outside.