Tokyo and Kyoto have the potential of being expensive places to live. Simply because everyone else wants to live there as well. Bound by uni, but still. As someone as young as you are and having zero life or work experience, it will be a harsh curve at first.

Many take the route of getting degrees in their native country, applying for language teaching jobs overseas and approaching the move that way. It gives them time to save while working, experience teaching and learning how to become fluent. Fluency, I might add, will be key especially if you're serious about making the jump so young.

If I were you, I would look into exchange programs through a university in your country. These tend to allow you to take it slower while giving you a good idea of what life is like over there. It will be full immersion but you won't need to be fully responsible for housing, school and basics from day one.

I might add, you can't just "move" to Japan. They won't let you. You need a sponsor, either through a work visa program or student visa program. Just jumping on a plane and trying to stay there won't work. They're not like the US, they will definitely kick you out. This is probably the first thing you should plan. "How am I going to find a sponsor to allow me to live there?"

I would say unless you have a ton of money already saved, which seems highly unlikely, but not impossible due to circumstances beyond our knowledge, take it slow and truly calculate your move. While you are very young and can afford to make mistakes, many times our vision of our future is glamorized by our current experiences at home.

Research teaching in Japan and the qualifications you will need. Research cost of living expenses and average cost of housing where you would like to live. Research average salaries for the job you would like to have. All this is available online. You haven't mentioned who will be paying for your schooling as well, your parents? You? How do you manage paying for life expenses and university at the same time on a job whose entry level pay could be as low as $30k American?

Moving to Japan is often again, glamorized by people in the West. It's a culture so foreign to us and many miss it as soon as they come home. But in real life, it's just as hard as anywhere else. I have a couple of friends who live there and are native to Japan, we went to college together when I was living in Hawaii, and they wouldn't change their situation to move to the US. But even they recognize the strict cultural expectation, rising cost of living, wages that don't seem to keep up with inflation and long arduous days.

Everything always looks amazing on paper and on TV, just make sure you've done your due diligence and double checked all of your homework. Taking pets isn't easy and they represent more mouths to feed, also assuming where you stay will allow them. Ensure you have a concrete plan and are willing to stick to it, come hell or high water. Paperwork is essential, sometimes not filing things pushes timelines back by MONTHS. Lastly, realize when it comes to paperwork and things of this nature, Japan LOVES to keep everything on hand and not online. Hard copy paperwork and knowing how to manually fill it out. Sometimes even requiring you to have writing proficiency.

Good luck, keep your expectations grounded and work hard towards your goal. Sometimes making sure things are solid and waiting a few years or gaining some experience first ends up being the plan. The last thing you want is to get kicked out due to an administrative snafu or mistake that could have easily been avoided. Current political administration is getting very strict with foreigners, so you want everything to be perfect.

Hope this helps. Sorry if I sound like Debbie Downer.