The startling aspect of this notion is that if Jesus was fully human and “grew in wisdom” that means that his sinlessness wasn’t in that he always knew everything and had all the answers so much as that when he faced any decision, he always chose the right path, the godly path
Too often in Christian circles faith is equated with more certainty. More certainty means more faith. The truly mature do not doubt, or so the line goes. But that is a Western cultural perception that has everything to do with how much we live in our heads and intellectualize faith and very little to do with how Scripture describes the essence of a faithful life.