This quote comes from the book Sula by Toni Morrison.
In this quote, we are told that the two protagonists, Sula and Nel, had realized by the age of 12 that they were neither white nor male, and that this was a disadvantage. At this point, the two of them were very young, but they were already seeing the racism and sexism that would plague their lives. This passage allows us to better understand the setting in which the story will develop. It is also an example of foreshadowing as it helps us anticipate some of the problems that the girls will face throughout their lives. Therefore, the passage is a commentary on race and gender issues in the United States.