Personalized Cutest Big Sis To Be Youth T-Shirt. Cute future big sister Youth T-Shirt - Heather with bold, colorful text and hearts says Cutest Big Sister To Be. 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.