Play is such an important piece of the PreK 4 curriculum. Everyday we play, they are learning so many vital skills to help them get ready for kindergarten. The children not only learn academic skills, but social and emotional skills as well. I found this quote found below, and thought you might enjoy it too. The author Gordon Neufeld, wrote the books Hold On To Your Kids, and Loving By Leading.
Also- here is a link for help with the emotional development of your child, it's the New York State site that all PreK and Kindergarten teachers rely on for guidance, and have been trained in. I have linked the parent page for you below. I hope it helps! :)