Personalized Cute Turtle 6th Birthday T-Shirt. 6th birthday I'm 6 T-Shirt - Light Blue with happy smiling turtle with bow tie and party hat holding balloons and big red polka dot number six on his tummy. Everyone loves our Custom T-Shirts! 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.