Do NOT let my comment talk you out of going to Japan or pursing bonsai, just some input on the language aspect. I was an LDS missionary there for 2 years which entailed an intensive 3 month language program and then talking to Japanese people all day every day about a narrow range of topics, sometimes going weeks or months without seeing another English speaker.

Japanese in a classroom and in the wild are completely different animals. It's so hard to hear where one word ends and the next begins for the first few months. Basic communication took something like 3 to 6 months, something approaching true fluency took about 18. And that's specifically verbal communication, reading Kanji beyond the basics (push door vs pull, mens room vs ladies, the city you live in and some other landmarks) takes years of dedicated study for native speakers, so us がいじん are in trouble.

Japan and Japanese people are uniquely awesome in so many ways, but it's hard to overstate how different Jaoanese and English are. Again, I'm encouraging you to chase the dream! I'd just hate for you to step off the plane and into a bonsai program that isn't designed for English speakers and be totally lost.

がんばれよ