well, for me, i began learning english in middle school and then all along high school but after a total of 8 years our level is more or less an intermediate b1-b2 . Instead I really learnt english in university because i'm majoring in health science i had to read plenty of reviews and scientifical papers, i would say that the most important think to learn english is read books, papers, and everything you can get your hands on in english, but also listen and see films in english, that will surely help to perfect the other skills

I don't know. I'm learning English and German almost every entire day.