In the United States, public kindergarten enrollment typically requires children to be five years old by September. However, private schools, without state-mandated cutoffs, provide an alternative option. Using American Community Survey data from 2008 to 2019, I examine the relationship between children's birth quarter and their likelihood of attending private school. I find that children born in July to September and October to December are more likely to attend private kindergarten than those born between April and June, an effect that is not observed in higher grade levels. These findings suggest that the entrance age cutoff influences parents' school choices, and they use private schooling to ease the cutoff constraint and initiate their children's formal education, later transitioning them to public school as they advance through the K-12 system.