I am entering my junior year (of hs) and I am also looking into studying abroad in college (in Japan). Japan is very expensive so I suggest saving up or learning enough Japanese to get a job. I heard English- tutors there get paid nicely, so maybe you could use that as a source to your income. But the bottom line is that if you want to go to Japan, don't let little problems get in your way. Go do it anyways because it's what you want to do.
I would recommend taking a lot of Japanese courses in the summer, online, after school, or just getting a tutor.
Good luck.