Personalized Rocket 4th Birthday Toddler Long Sleeve T-Shirt. Happy 4th Birthday! A rocket blasts off from an alien world with a giant 4 for the four year old's fourth birthday! 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.