Personalized Superhero 4th Birthday Pink Women's V-Neck T-Shirt. Happy 4th birthday! Celebrate your toddler's third b-day with this cute I'm 4 pink superhero design. Happy Birthday four-year-old! 5.0 oz., 100% pre-shrunk cotton Athletic Heather is 90/10 cotton/polyester 1x1 rib collar with mitered v-neck Shoulder-to-shoulder taping Ladies' fit