I was on the JET program in a small town in Hokkaido for the maximum number of years I could be. I majored in East Asian studies with a minor in Japanese and it still took a while for me to get used to being immersed in the language. Small towns and even small cities don't usually have the type of animation school you're looking for. You'd have to either be in a more major city or commute.
One other factor is the culture shock. A lot of JETs suffered from this and a fairly high percentage only stayed for one year. If you've never visited or lived in another country before, then being suddenly immersed in a different culture can be very overwhelming. You also need to be aware of and respect cultural differences.
Cost will vary, but if you're looking to rent your own apartment, you'll have to go through an agent and probably pay key money, which is monthly payment upfront and can sometimes be as much as half a year to a full year's rent if you're a foreigner. There's also a lot of initial set-up of bank accounts, phone, electricity, etc that you will have a hard time doing if you can't speak the language. The advantage of something like the JET program or other language schools, is they help you and have a person assigned to you. If you're going on your own, you won't have that. If you're trying to save up to move there even for just a year, my guess is you'll need at least $60,000 (that's just for living expenses, not including paying tuition).
My advice is similar to others above me. Find out if there are language classes you can take near you or online if you are really serious about going to Japan. You'll need to register for the Japanese language proficiency test months in advance of taking it, and there are limited places you can take it so you'll have to research which cities it's offered in.
If you have a Japanese consulate in your city, contact them. They will have information about language classes and ways to attend Japanese institutions.
Also, because of Covid, Japan has banned the entry of pretty much everyone indefinitely, so no going there for a while.