Personalized Rawr I'm Three Dinosaur Youth T-Shirt. Rawr! I'm Three! A cute T Rex dinosaur holding a megaphone and wearing a birthday party hat roars to let everyone know its birthday is here. Cute gift for your three year old's 3rd birthday. 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.