I'm 12 and want to live in japan

I'm currently only 12 years old and living in the UK but in the future possibly when I'm like 20 odd. Ive searched up all costs for apartments and when I can rent them. Ive also trying to be learning Japanese but I'm still not sure how to go the best way around it. I understand about the noise and culture and such but even though ive researched it i still don't really know about it. If any of you people out there who's been to Japan or what please give me some insight. I thanks

Best is to first finish your school, high school and university.
Focus on the language and try to network.

Searching for housing etc has no meaning since prices will decently change over 8 years

https://blog.gaijinpot.com/japan101/visas-and-status-of-residence/
https://www.mofa.go.jp/j_info/visit/visa/long/index.html

First study and finish your school, preferably up to university.
Why? See above link and understand the types of visa you need to start living in Japan.

https://www.mofa.go.jp/j_info/visit/w_holiday/index.html
If your are of UK citizen, than you are good for Work Holiday Visa (up to 1 year stay), which is easy to get and can be a way to experience living/working in Japan.
Then you decide whether living in Japan is the thing you want, and go the proper visa way.

A lot can happen in 8years, so finished your study, learn Japanese and start making friends. Or try some exchange/homestay if you could.

Living Japan is not just about Games/Anime/Jdrama.

(Games/Anime/Jdrama)

this is so true. It is hard working and especially for foreigners life can be difficult.

Learning about the cost of things is one thing, getting someone to pay you money to pay those bills is quite another. A discussion with your parents about work/income and bills/expenses might be useful.

And life in Japan for a foreigner can be difficult, frustrating, confusing at times, but can also be rewarding.