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 had these as a kid myself almost 30 years ago and just ordered the first pair (size 20) for my daughter. They are fantastic. Even though she has only been walking for two months or so, these wellies aren't too bulky or clumsy, she can run and walk in them just as well as in her normal shoes. They fit snugly but are easy enough to put on. I will definitely buy these again when she has outgrown this pair!