Personalized Class of 2021 Rocks Light Youth Long Sleeve T-Shirt. Class of 2021 rocks text with three happy dancing rocks holding class of 2021 flags is a humorous gift design for school students excited about graduating in 2021. youth long sleeve t-shirt. Shoulder-to-shoulder taping. Youth: S(6/8), M(10/12), L(14/16), XL(18/20)