Personalized 3rd Birthday Mermaid Tail Girls Party Toddler T-Shirt. 3rd birthday Toddler T-Shirt - White party idea has starfish and mermaid tail with this mermaid is 3 message A toddler-soft cotton tee in look-at-me, big kid colors. 4.5 oz., 100% combed ringspun cotton. White is sewn with 100% cotton thread. Topstitched rib crew neck. Double-needle stitched sleeves and bottom hem. Shoulder-to-shoulder taping.