International schools in Tokyo Gr 12

Hi there,

I have this amazing opportunity to move to Tokyo in my Gr 12 year. However, it will be my last year of high school before university and I'm having lots of doubts and I'm looking for some advice.

Being half and visiting Japan annually, I've grown to love the country and I'm extremely interested in studying/living in Tokyo for a full year. I plan on going to a university in my country (I feel that the education is stronger here) and I feel like this would be my last chance to study abroad in Japan. I know this would be a great way for me to grow and gain new perspectives and I won't have many opportunities like this! My jpn ability isn't very strong (conversational and low reading/writing) and I hope this could help me improve and be more closer with my background as well? (If that makes sense)

I'm unsure of what I want to study in university (or the rest of my life really) as well and I'm hoping this experience could give me a new perspective of what I would like to pursue?

I guess my overall questions are:

Is grade 12 too late to study abroad?
Will it affect my admission into university in a negative way?
Do you know which international schools are best?
(I've done my research, but if anyone from the inside could tell me about their own experiences)

I also understand that International school is wildly expensive and my parents, who do agree this would be a great opportunity for me however have avg. incomes, would be making a HUGE investment in me.

Is the experience worth it? Would the education be worth the tuition?

Thank you.