You might want to focus on the beginning of chapter six, and the perennial conflict that exists between Antonio's parents. As Antonio gets ready for his first day of school, his father says that this is just "another expense," which results in an argument between his parents about his father's dream of going to California, and his attachment to wandering around on the moors, whereas of course Antonio's mother wants him to study so that he can become the priest of her people, the Luna family, who are successful farmers in the valley. Note how the mother responds to the father's reference to California as a land "flowing with milk and honey":
"Any land will flow with milk and honey if it is worked with honest hands!" my mother retorted. "Look at what my brothers have done with the bottomland of El Puerto--"
We can see that this is a central conflict in the whole book, and results in the internal conflict that Antonio suffers as he believes he has to choose between the two mutually exclusive paths his parents want him to follow.
I suppose you could reflect a lot on the parental pressure that children face as they grow up. Sometimes this can carry on even into adulthood as parents have very fixed ideas and hopes of what they want their children to be. However, the novel's overwhelming message seems to focus on the way that we must find our own path, and if necessary not fulfill the dreams and goals that our parents have for us in our own quest to discover ourselves and establish our own identity.