Personalized Rawr I'm Three Dinosaur 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. Everyone loves our Custom T-Shirts! Wardrobe essential for looking good, 24/7. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar. Shoulder-to-shoulder taping. Double-needle stitched sleeves, bottom hem and front neck. Note: greys are a cotton/polyester blend.