Personalized Sweetest Big Sister Youth T-Shirt. Who's the sweetest big sister? Cute Youth T-Shirt - Kelly Green with adorable smiling cupcake with pink frosting and red cherry on top says SWEETEST BIG SISTER. Let the good times roll in a durable T-Shirt that takes kids from school to play in an amazing array of colors. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar.