I have seen articles that imply that He was trained by rabbis and scholars. We know so little about His childhood and even adulthood until He started His ministry, don’t we?
Well, there is no definitive statement about him being trained, but, in the absence of that, I would assume that he wasn’t.
After all, we do know that, as a child, Jesus could stand up in the Temple and hold discourse on the Torah that impressed his elders. So, he apparently had all the knowledge one would expect the author of the Torah to have. Why would he need to be trained by a human with less understanding than he possessed?