Personalized 4th Birthday Party 4 Year Old Boy Toddler Long Sleeve T-Shirt. Childs cute four year old birthday design has bear riding a bicycle with hooray Im four quote. 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.