In her narration, she listed many lessons she learned. I think, the primary lesson she learned is the lesson that she heard the reason she was chosen to host PTA show over the other black boy by her family has more money other the black boy's family.
One way to interpret this story is to see it as a tale about a person who is part of a multitude of cultures and identity groups. The young girl who is the protagonist of the narrative is simultaneously (1) a girl; (2) a Puerto Rican; (3) part of the middle class; (4) light-skinned rather than dark-skinned; (5) a sometime resident of New Jersey; (6) a member of a particular family composed of particular personalities; (7) a primary school student; (8) a speaker of Spanish; (9) a speaker of English; and the list could go on. The important point is that she is shaped by all these different cultures and identities, some of which are in conflict and some of which are in harmony with one another. One "lesson" the girl seems to learn is that she is indeed affected by all these distinct influences. Another lession she learns is that because she is a child, she must meet the expectations of adults.