The natural solution to your problem, longfortheblur, seems to be this:
1: Accept your parents' generous but extremely myopic offer to pay for your college tuition.
2: Go to college in the USA. Do a degree in something which interests you. If you can get a degree in Japanese Studies that would be perfect, but your parents are extremely likely to smell a rat
Do you like computers? Get a BSc in something which will enable you to work with them. Do you like art? Do a BA in something which will enable you to get a job as an artist. Get a degree in something that you can spend the rest of your life doing for a living.
3: STUDY JAPANESE IN YOUR SPARE TIME. Find a Japanese restaurant who's hiring wait staff if at all possible. If you can speak Japanese but your reading is ropey, spend your spare college time learning to read. Do not spend your spare college time going out, getting drunk, vomiting in your roomie's bed, then waking up at 3pm and missing your lectures.
4: Aim to pass the JLPT 2 (at the very least) by the time you finish your degree. Bear in mind that the JLPT is only administered and marked once or twice a year.
5: Leave uni with your degree and apply for jobs either with Japanese companies in America, or American companies with offices in Japan. Make it clear on your application form / covering letter that you intend to move to Japan, are fluent in Japanese, and are just awaiting the results of JLPT (whichever level you sat).
I know, it's a pain in the arse waiting another four years. But trust me, trying to get into Japan without a degree isn't going to get you far. You'll thank yourself when you're 25 and living in Japan
