Personalized Third Birthday Unicorn Girls Toddler Long Sleeve T-Shirt. Three year old birthday party design with unicorn riding a scooter and 3 balloons for a toddler girl. 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.