No one knows, His life is pretty much a ‘tabula rasa’ until the age of 24 or so.
But there are many theories.
It is only our understanding of His life until 30 that is a blank slate, it was fully developing in secret, the same as how He was saved from Herod by secreting Him in Egypt, “The dragon stood in front of the woman who was about to give birth, so that it might devour her Child the moment He was born. She gave birth to a Son, a Male Child, Who “will rule all the nations with an iron scepter.” And her Child was snatched up to God and to His throne.” - Revelation 12
Since Jews put a premium on learning scripture, Jewish fathers were admonished to begin teaching their sons the Torah as soon as the boys could talk. Then at five years old they studied scripture with a rabbi; at ten years they studied the Mishnah, at thirteen the commandments, and at fifteen the Talmud. In all likelihood this is the path Jesus followed.