Hey! Welcome to the forum! I am sure that their are people here that have suffered from similar injuries. Professional MMA fighters have come back from this type of injury as well. Patrick Cote actually just fought for the first time recently since tearing his ACL.
Things to know are simple at first. Just work hard and have fun. Stay dedicated to your training. Have an open mind and most of all, do not be afraid to ask questions. It will only set you back if you don't fully understand what is being taught to you.
I think you should pursue it even after your knee injury. Just try hard not to injure it again. You need to know your limit and if you are hurting your knee, just take it easy for a bit.
Good luck! Remember, have fun and train hard!