You cannot go back. You wouldn’t if you could. OH! No! You simply wouldn’t be the one you are today if you became that young one way back then again. I do not mean a “no” in terms of time travel, as neither do you. Since you did not mean that you grew out of a garden of a paradise from back then nor did you mean that you came from a better world from back then, since you did not argue from either of them, then neither shall I. If the knowledge you have today were yours back then you would have been alone in the world with it. Was the world ready for you as you are now back then? If the world is not ready for you now would it have been ready for you back then? What ever you have learned the hard way or some other way was maybe not even known back then and that is why you never got it then. Those who taught you and exampled for you did not know to teach you or did not bother to teach you, either could not or refused to set examples for you to learn from. The knowledge in those senses I give means the knowledge wasn’t, effectively, even there. Now you know from your life time, such as it is, and life experiences, such as they have been, and from your ruminations, reflections, conclusions, and your desiderata, what you claim you now know.
The child with such knowledge as you have now and living amongst the rest of the world back then would be pitifully outcast. I do not mean with knowledge of computers and modern accoutrements, nor did you, but who would possess more social and human relationship knowledge, skills, and abilities than anyone around them. No one would understand such a one who would be called something akin to “child-being” and who would be an alien in the social arena.
To put it crudely and in the extreme, if you were now a younger but knowledgeable you set among anywhere anytime, you would not be alive long amongst the most advanced of any ancient time, even with also a collection of the most modern accoutrements. Either you would end it from being so incongruous or they would end you.
All of this I guess you already vaguely figure intuitively.
The “you” that is you sits and sees from atop the summit of an accumulated mound of the entirety of the memory, the entirety of the how you came to think and came to know anything. You are the result also of the struggles to come to have what you have. You are the result also of the struggles to come to know what you know. You are the result also of the struggles to come to be whatever it is you are. You are the end result of your struggles to survive. You are the end result of your disappointments, embarrassments, humiliations, and failures. You are the end result of your successes, earnings, learning, and works. You should not wish that changed. OH! No! You shouldn’t! Because such a change would entail and guarantee that you would, very simply, not be you. Such a change would entail and guarantee you would not know yourself, would not recognize yourself, and would not have any knowledge at all. No, you wouldn’t, no, not without all of, may we just say, all of “that”. All of “that” is what you really are. All of “that” is what made you “you”. Even if you are a monster or some disgusting freak, you are still even if undeservedly but nevertheless necessarily all of “that”.
To put it crudely and in the extreme, if you were now a younger but knowledgeable you set among an anywhere at anytime, either you would end it from being incongruous or they would end you. If you should impart what you now know to some one now as young as you want, that one would still have to come to understand what you know plus live and learn and come to know the world as it now is. They might be better for all you impart but would have to have a new list of problems and puzzles and complaints all new to you. And you would necessarily become incongruous to them. Such is so that you would become what is called the dinosaur or "old". That it seems is the result in even societies that supposedly never change.
And you wish you could live a thousand years!