Yeah, for those returns I wouldn’t have done it. I go to a private language school, where the teacher teaches Japanese 6 times a week at various levels. I started November 2017 with barely any knowledge, joining a class at chapter 3 of minna.
I had a lot of time, so I was able to work ahead and join the class that was already at chapter 18 after working up to 14 on my own. After that I was again able to work on my own and catch up to a class that was working through chapter 38 at that time.
That’s where I am now, with an eye on the highest level class (which has an N1 as a student as well). They are currently early into the second chuukyuu book, so I am about 23 chapters behind them.
So for now I will go to both classes, held on Tuesday and Thursday evenings. It is a trainride away, but at 3 hours a night, well worth the trouble and euro’s (especially since I pay per 12 week season, but I can go how often I want during that period). Also a lot of outside of classtime support by the teacher and senpai.