This means that he has to be consistently looking back retrospectively, not just when it's convenient.
And the level of wisdom gained by his older and wiser self will influence how he says everything.
Yes, he can withhold information for drama, if it's in character, because it's clearly his telling of the story with intention and for some purpose. But the character telling the story needs to be as consistent and convincing as the character depicted in the story.
(Which means he might only comment at one point. But then, you can do anything if you can do it, and that's a hard one to do.)
Furthermore, we have to be convinced that the character telling the story could be the older and wiser version of the idiot in the story.