Personalized Yay! 41 Fun Youth T-Shirt. Yay! 41 and ready for fun text in a decorative swirl is a fun design for friends and family at birthday time. 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.