The text can be divided into several parts.
The first part is an introduction. It develops in 2 first paragraphs, where Sylvia writes about the routine, that every day the life is rather monotonous. To show this the parallel construction is used (wash a blouse, think a thought, write a letter).
The author resorts to such stylistic device as polysyndeton (another tooth and another and another) and it depicts the quickness of the life. The author enhances the desired effect with the help of the parallel construction, which is used in the ironical slant (…and before you know it, little Suzie will start going to school, and her troubles will just begin).
In the introductory part the author employs to the epiphora (they keep promising that things will be different), irony (improved conditions) and antithesis (conditions seem greatly unimproved) to show the disappointment of the main character.
As this text is a letter we can meet here some colloquial expressions