Personalized 3rd Birthday Space Rocket Boys Youth T-Shirt. 3rd Birthday childs rocket blasts off to outerspace on this Youth T-Shirt - Pacific Blue with I'm three celebration slogan, a great party photo gift for boys or girls turning 3 years old. 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.