Michael Schoch, Answers questions on Noodle
Unfortunately, I couldn't find specific information on Wonder Elementary School's preschool classes. My recommendation would be to call the school at (870) 735-4219. Many preschools require that students be 4 years-old by September 1st; however, this isn't a universal requirement only a common one.
Sorry I couldn't give you a more definitive answer. I hope this gives you some resources. Best of luck!