Personalized I'm One Long Sleeve T-Shirt. Stop counting my age in months. Cute, funny toddler tee for your baby. Happy Birthday 1-year old! Pre-shrunk 100% cotton 6.1 ounce long sleeve t-shirt. Double-needle stitched neckline and sleeves. Quarter turned. Shoulder-to-shoulder taping. Adult: S, M, L, XL, 2XL, 3XL