Personalized I'm Three Comic Book Toddler Long Sleeve T-Shirt. Pow! Cool! Ka-Boom! I'm Three! Cool comic book style birthday gift for any three year old superhero's 3rd 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.