I think you should go to Japan for a month or two to see if it is really where you want to be. Once you get the feel of the country and experience day to day things for a few months your opinions change either for the better or for the worse. You wouldn't want to move your whole life to Japan only to find out you don't like it.
It's always good to dream though and set goals so I hope you get to where you want to be regardless.
