Amazon calculates a product’s star ratings based on a machine learned model instead of a raw data average. The model takes into account factors including the age of a rating, whether the ratings are from verified purchasers, and factors that establish reviewer trustworthiness.
I bought this to help prepare my kid for starting kindergarten. However, the story focuses on Uni figuring out how to help people and to be patient, and it's really not about being nervous or enthusiastic about starting school. It's a cute story, though.