Personalized 1st Birthday Puppy Toddler Long Sleeve T-Shirt. I'm one cute puppy. Celebrate your baby's first birthday with this adorable little doggie. Happy 1st birthday one-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.