For a bit over a year now. I highly recommend it, I wrote a bit about my experience when I started in this other post:
https://steemit.com/martialarts/@irime/from-outsider-to-part-of-the-team-the-five-stages-of-the-social-experience-in-brazilian-jiu-jitsu

The most difficult... I think probably the fact that the learning curve is super steep and therefore there is endless frustration and confusion; during some periods you feel like you are not getting any better or you don't "get" what you are supposed to be doing. But this pretty much standard experience, you just have to persevere and keep trying to improve and eventually you will.