That whole thread was a wild ride… it’s amazing that you are so thrilled to start a new life, but as multiple others have already pointed out, take a deep breath and try to think about it rationally. No one is trying to rain on your parade, but it seems like you and your sister totally misjudge the whole situation and might run into major problems down the road if you don’t think this through and approach it slowly.
If you both want to go to Japan - yes. There are ways. But I highly doubt they can be achieved that quickly and easily as you (both?) might think. And the language is the least of your problem.
I have lived in Japan for some time - my company has a branch in Tokyo and I was working there for a year. And again - visa is no joke. I was so glad that I had assistance from both my office and also the Japanese side, because I would have just cried in a corner with all the application guides. Also I have a university degree in Japanese. So if you both want to work in Japan, maybe also consider joining a company in the US first which also has a branch in Japan and offers some exchange program. And yes, it will take years, but that should be worth it, if it’s your dream.
A friend of mine is going to study in Japan next year - hopefully. If covid allows it. She is N2 level (passed JLPT already), an amazing high school student with the best grades and already reached out to teachers last year, because she needs support on this. She does complain every once in a while that the applying is a nightmare - even with the help of her high school teachers and Japanese teacher and a tutor. I would always advise you to get some teacher to help you figure out how to study there if this is your plan. They usually know scholarships (also which one would be good for you) and how to apply - or have the better connections to even look it up.
Next story: I have friends living in Japan. One is married to a Japanese man and has a daughter - yet she needs to re-apply for her visa (I think every other year? Though last time she said she got a longer span, which even surprised her). She is super nervous, every single time. She is N1 level, has been working in Japan for 9 years, has been married for 4 years, daughter is 2. Still. Visa. We are all serious here when we say the visa is the biggest obstacle.
The whole car and dog story does worry me a bit. Because… yeah, I think you are both just super excited, but don’t really have any idea what you are even trying to do… For instance the car: I don’t think this would be a wise idea at all. It first depends on where you live. If you aim for a bigger city, you won’t need it. I am also in doubt you can just drive an American car in Japan. As some have pointed out, you even drive on the “wrong” side of the road for you. Also housing. Some have mentioned it here as well, but not everyone is happy about foreigners in Japan. You will meet racism. I never expected it to be this bad, but yes. You run into it, even in Tokyo. I thought it was a joke that people would refuse to sit next to you on a subway. No. They got up as soon as I sat down. As far as I know there are still restaurants, which won’t allow foreigners? Though I wonder if Olympia at least has tackled that. I really thought this were just myths. No. You run into a lot more problems than you can think of.
A lot of tennants refuse to rent to foreigners. It’s already annoying enough for a Japanese person to find an affordable apartment in Tokyo; double that trouble for foreigners. And if you say even two dogs… costs aside, but this is something immensely you want to tackle within a year. You can’t just land in Narita with two dogs and say, let’s find an apartment. This is really way too illusional. I could barely fit a friend in my apartment for a sleepover. But to live with my sibling and two dogs… how would that even be possible. Sleeping on top of each other?
And something I just want to warn you about, because that hit me extremely: culture shock.
I have been interested in Japan since forever. I had studied it during high school on my own, I studied it at university, graduated even. I thought I knew how life would be there. But the culture is different. You will feel homesick. You will run into things that will not suit well with you. I always thought I wanted to stay longer, because I enjoyed my holidays there, but living there… I was glad when I could go back to good old Europe after that one year. I had friends there, I had a secure job, I could read and talk with Japanese people. I wasn’t lonely, and yet I knew that this would never be my home.
Before starting a new life half across the world with no way back, I would visit said country first. Multiple times. And yes, not possible right now, but your plan to live in Japan will take time either way, so you have a lot of time to think it through and study. Japan is not anime-land. I know it often sounds too good, but it’s really not for everyone. Which is absolutely fine! That’s why I think student exchange programs are always the best start. You have a set time in which you will live there and you will also figure out how life really is there, and if you will ever will feel home. I did read that you have a hard time at home now and the thrill to escape is all too familiar to me. The further, the better, right? But it doesn’t have to be Japan. Japan can always be your favourite vaccation country.
And last, I might sound strict on this one, but I do mean this with the best intentions and I don’t want to sugarcoat it.
I think it’s not really fair how you drop the responsibility on your sister. You said quite often she has invited you. She might have, yes. But you still need to apply for your own visa, you will still have to provide half the rent, you will still have to figure out how you want to live in Japan. You can’t just drop everything on her. What if she marries? You will just move in with them? Do you even know how small apartments are in Tokyo? What if she can’t pay half of the rent due to unforseen reasons? What if she wants to move back after a year? What if she wants to move to Australia next? You will just follow her wherever she goes? You can’t always just tell her, “But you invited me”. That’s not how it works. You will want internet, a phone (and those stupid phone plans are expensive!), you need money for public transportation. You can’t just always say, “But you invited me” and not provide for yourself to 100%. Whenever people asked you here about how you will approach it, you often said, “My sister invited me”. Yeah, she might have given you the idea, but honestly. You have to figure it out on your own.
You might want to move to Japan as siblings, but you cannot depend on her like this, you need to be equal partners. You have to treat this as if you would move on your own. She might also run into problems and then she might need you to help her through and offer her advise, and not someone just saying, “but you invited me!”
Moving to another country does mean you have to be an adult for yourself, so you have to start acting like one. Figure out if you want to study or work. You first said working, then suddenly studying, then back to working. It doesn’t work like this. Japan is not America. You need a strict plan. Figure out what you really need for visa. Not just skip over it and think “oh yeah yeah, awesome”. Sit down. Read. Make a list what you need and how you can get it. It will take time, probably years. And that is good, because you need to be ready. Not just “wheee, I am ready for a new advernture”. Japan isn’t like this, it’s much stricter than you are used to in the US.
The time when you figure out how to move to Japan is part of your big journey, and also a time you should enjoy. Not just grab a suitcase and run out of the door - you are most likely to fail with this approach and no one here wants to see you fail. Everyone is here to offer you advise and help you step by step. If you are serious about this, be prepared that it will take years and lots of hurdles. But if it is your dream, it will be worth every second that you are investing.
I wish you and your sister the best of luck!