One 1st Birthday Princess Personalized T-Shirt. Time for a royal birthday! Your little girl will be princess for a day in this 1st Birthday Princess Personalized T-Shirt. Simply enter your child's name in the 1st Line box of the Product Options to the right, and we'll print it below the design on the t-shirt. Browse our fantastic selection of Princess Party Supplies, from tableware to party favors, and make your little one's first birthday a magical one.