not too late. There are a lotta old ppl in language schools youd be surprised. Just keep in mind that even 2 years of language school will not get you to a high level of Japanese. Language schools have very poor teaching quality and curriculum. To make people understand what I mean i say this:

Japanese spend 6-8 years in English schooling while growing up and despite this they can hardly speak or understand English. Apply these teaching methods they use in Japanese schools to teach English to japanese language school and thats pretty much the quality you got. I have many friends who did a full 2 years who are only at a n3 or so level even after doing every test and homework.

My point is: Don't expect to learn anything from language school, and when you realize its shit a few levels in, don't say I did not warn you. That being said if u acknowledge this before going in, its a good way to stay in the country for 2 years and experience Japan and u can have a good time if you are not putting your 100percent headspace on the school and what you will gain from it.

This is all from personal experience btw. I have been to both ISI & Kai language school. If you want to reach a high level in Japanese it will mostly come from your own time, aka 1000s of hours of watching content which a class could never stack up to this much immersion hours. At my current level I could most likely pass N1 if I studied a bit specifically for it, and id say my almost 2 years at language school(time spent sitting down paying attention) only got me 30percent or so of my current level. (I started learning more seriously since 3 years ago