The gospels tell us very little about Jesus’ early life. The most relevant verses are in Luke 2:
And the child grew and became strong, filled with wisdom. And the favor of God was upon him. (Luke 2:40)
After three days they found him in the temple, sitting among the teachers, listening to them and asking them questions. 47 And all who heard him were amazed at his understanding and his answers. (Luke 2:46 – 47)
And Jesus increased in wisdom and in stature and in favor with God and man. (Luke 2:52)
We would expect that Jesus was educated both at home and at the synagogue, as appears to have been usual. However, his wisdom and understanding was so very unusual that this cannot have been his only method of learning. I assume it came from a combination of wisdom and instruction from God, from his parents, and from his school as well as considerable time spent learning and meditating on God’s word.
John 7:15 – The Jewish authorities were greatly surprised and said, “How does this man know so much when he has never been to school?”
Thanks for your comment. What John 7:15 actually says is that he was uneducated or had not been instructed, not that he had never been to school (compare ESV, NIV and NET). It is generally considered that in those days most or all boys learned to read and write at a synagogue school (see for example
http://bibleresources.americanbible.org/bible-resources/bible-resource-center/about-the-bible/bible-history/education-ancient-israel ).
In the context of Jesus himself teaching with authority in the temple, it is more likely that this verse is talking about him not being educated by another religious teacher (rabbi) as other rabbis were (including Paul). He had not had this special religious training, and yet he had set himself up as a religious teacher and they were surprised at his knowledge and competence in teaching.