One 1st birthday T-Shirt by Mud Pie. Size 12-18 months. This fun shirt is perfect for celebrating your little girl's first year! This jersey tee features keyhole short sleeves with bow detail, confetti sequins and a sequin "1" applique with pom-pom and a tassel jersey party hat. Dress her in this cute shirt for her birthday, and then she can enjoy it all year long.