Personalized 1st Birthday Unicorn Kitty Toddler Long Sleeve T-Shirt. Adorable rainbow unicorn kitty celebrates your baby's 1st birthday. I'm One! Cute first birthday gift for your one year old. A classic for Fall, Winter and Spring, these long sleeve toddler t-shirts are sure to be a staple in your child's wardrobe. Whether layered or alone, this t-shirt is soft yet durable enough to stand up to your toddler's playtime demands.