Personalized 3rd Birthday Outfit Unicorn Toddler Long Sleeve T-Shirt. 3 year old birthday gold unicorn Toddler Long Sleeve Tee - White 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.