Personalized Cowboy 3rd Birthday I'm Three Toddler Long Sleeve T-Shirt. Cowboy 3rd Birthday Toddler Long Sleeve Tee - Light Blue has cute striped number 3 with cowboy hat and lasso for your little cowboy's special birthday party. 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.