Personalized 15th Birthday Cupcake Long Sleeve T-Shirt. Cute pink 15th Birthday Long Sleeve T-Shirt - Pink has chocolate cupcake with sprinkles on this adorable 15 year birthday celebration gift for her. 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