Personalized T-Rex 3rd Birthday Youth T-Shirt. T-Rex 3rd Birthday! A cute T-Rex dinosaur holds a bright red balloon to celebrate the three year olds third birthday! Adorable gift! 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.