The next important ceremony after Annaprasana and Namakarana in a Hindu child's life is the Mundan or Chadakarana when the baby has his first hair cut. The Mundan ceremony can be done in the 1st year, 3rd year or 5th year of age but it is normally done before the completion of three years of age of the boy.
Please note that Mundan as a ceremony is prescribed only boy babies but today with the changing times, it has become a practice to have the ceremony done for girl child too.