Personalized 100th Day Of School Pencil Youth Long Sleeve T-Shirt. 100th Day Of School gifts. Smiling School Pencil Youth Long Sleeve T-Shirt - White for the teacher celebrating this school milestone each year. youth long sleeve t-shirt. Shoulder-to-shoulder taping. Youth: S(6/8), M(10/12), L(14/16), XL(18/20)