Luke 2:41-43, 46-47

Now His parents went to Jerusalem every year at the Feast of the Passover. And when He became twelve, they went up there according to the custom of the Feast; and as they were returning, after spending the full number of days, the boy Jesus stayed behind in Jerusalem. But His parents were unaware of it

Then, after three days they found Him in the temple, sitting in the midst of the teachers, both listening to them and asking them questions. And all who heard Him were amazed at His understanding and His answers.