Personalized Purple Dinosaur 3rd Birthday Youth Long Sleeve T-Shirt. LIL' THREE-OSAURUS 3rd birthday Youth Long Sleeve T-Shirt - White with cute purple cartoon dinosaur and big polka dotted number 3. youth long sleeve t-shirt. Shoulder-to-shoulder taping. Youth: S(6/8), M(10/12), L(14/16), XL(18/20)