Personalized Musician Mom Worlds Best Youth T-Shirt. My Mommy is the Worlds Best Musician Youth T-Shirt - Black gift for children has colorful lettering and earth logo. 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.