Agree with Damicci (naturally). Use the time between now and then to really study the language AND Japan, save up money, and find the best travel deals you can find. ;-)
If you are in a position to manage it, I recommend a short trip once, though, and then coming back for a longer trip later on. The first time around, you will probably get a better idea of what you want to do on the second trip, and will have time to plan in advance.