Elizabeth is acutely aware of the age difference between herself and the "grown-ups" of the poem – Aunt Consuelo, the patients in the waiting room, and the naked women in the National Geographic. She always seems to have a sense of herself as different from adults. Yet at the same time, she is asking herself some pretty grown-up questions about her place in the world and her connections to other human beings. She may not even be seven yet, but we sense that this Elizabeth is going to grow up to be a pretty smart gal. We even have the feeling that the events of "In the Waiting Room" are what starts Elizabeth's journey into adulthood.
Elizabeth sees the similarities between herself and the adults in the poem and is convinced that she will grow up to be like them.
Adults are totally foreign to Elizabeth, and she thinks that she'll never understand them or their lives.