Personalized I'm Three Cute Birthday Bear Toddler Long Sleeve T-Shirt. I'm Three! A cute teddy bear has its own birthday cake to celebrate its 3rd birthday. Cute gift for the three year old! 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.