Devibhagavatapurana 3.17.40

3.17.40

varṣe caikādaśe prāpte kumāro'sau nṛpātmajaḥ |
muninā copanīto'tha vedamadhyāpitastathā ||

When the king's son grew eleven years old, the Muni performed his Upanayana (sacred thread) ceremony and made him begin the study of the Vedas. The son, with that mantra power, soon mastered all the studies about archery, all the moral and political sciences in conformity with proper rules, within a very short time.