Personalized 100th Day Of School Preschool Youth T-Shirt. Cute 100 Days Of School Youth T-Shirt - White shirt for preschool or pre-K parties. Let the good times roll in a durable T-Shirt that takes kids from school to play in an amazing array of colors. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar.