The Zebra Wall by Kevin Henkes

The Vorlob family is making preparations. Preparations for the new baby, soon to arrive. Getting ready includes painting a mural in the baby's nursery and making a list of possible names. Adine, age ten, is used to the routine -- she has four sisters already: Bernice, Carla, Dot, and Effie. This time, however, the routine is broken. In more ways than one. Most significantly, Aunt Irene will be staying with the Vorlobs until Mrs. Vorlob is rested and back on her feet. Aunt Irene arrives, as does the baby, but nothing goes quite as expected. Especially for Adine.