It takes arownd 2-3 years to learn a new languag but fluently 3-4 years.
I would add to Chanhco's answer that it depends on what language you learn and also what your native tongue is. And of course, how much time you dedicate to learning.
I think two years
I'm learning Polish over 4 years now and I am no way close to being fluent. A2--->B1 at the most. I'm have learned mostly on my own. My biggest mistake was that I didn't listen and speak it from Day 1. Everyone get out there and speak it out, it is the best and maybe only the only way you will honestly progress. Powodzenia!! Cześć.
You are doing a good job David, I can see you climbing on the leaderboard 😀
BTW, we have a free online live class with some Repeto students. It is on Wednesday afternoon 4pm UK time, would you like to join?