What is Esperanza in disbelief over?

In the story Esperanza Rising, Esperanza is disbelief over the sudden death of her father. Their family is a ranch owner in Mexico and when a person or family owns their own land, they are considered a few of the rich people.

She lived a luxury life with her parents and when her father died, she cannot imagine a life without him especially when her father’s siblings are after their riches. She and her mother fled via a train ride from Mexico to the United States where she learned poverty. Esperanza learned that poor workers exist and they live in the poorest conditions she could ever imagine and that there is a connection between race and class.