Personalized 5th Birthday Cute Unicorn T-Shirt. Celebrate your 5th birthday T-Shirt - White with this I'm 5 quote and adorable unicorn fantasy design. Wardrobe essential for looking good, 24/7. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar. Shoulder-to-shoulder taping. Double-needle stitched sleeves, bottom hem and front neck. Note: greys are a cotton/polyester blend.