Personalized Ninja In Training Youth Long Sleeve T-Shirt. Youth Long Sleeve T-Shirt - Royal Blue with adorable baby Ninja says NINJA IN TRAINING. Perfect for your little warrior. Baby Ninja used on this item is licensed and copyright from Graphics Factory.com. Matching NINJA MASTER also available. youth long sleeve t-shirt. Shoulder-to-shoulder taping. Youth: S(6/8), M(10/12), L(14/16), XL(18/20)