Racist parents? Banned from Japan.

Keep practicing your Japanese, as much as you possibly can. You may not be able to leave immediately when you turn 18, but when you can, you'll be ready.

Mari,
I have been on 3 sides of this issue. Until I was 19 racism was a part of my family. I could not listen to Japanese music, or most American rock at home. It was prevalent with my classmates also. I happened to learn something about Japan through NHK overseas radio, and acquired a Japanese pen pal (we did not have internet then). I gradually learned that the Japanese people were very nice people.
When I was 19 I joined the military. When was stationed in Okinawa for a year and a half, there I married my pen pal. I have raised 2 kids. And I have 4 grandkids, one a girl your age. So I know from a childfs, a parent, and grandparentfs point of view what is happening with you.
The best advice I can give you is to be super cool when dealing with your situation. Know what you want to do, and where you are going. Donft get angry and yell, or pout when dealing with your parents. Be more of an adult then them. I got good results when I dealt with my family with authority and kindness when my wife and I returned home after the service. My granddaughter acts more like a 40 year old than a 14 year old. She gets the respect of an adult form most people. I might add she gets her way most of the time dealing with adults.
I might add with some collage, even a 2-year degree it will be a lot easier to survive in Japan. Doors will be opened for you. There may be an opportunity for you to attend collage in Japan. Hang in there you will make it.
Japan is still in my heart. I wish I could live there, but due to circumstances I cannot.