Hi. If you are fit now, you will recover just fine. Time is very individual. I had my inside right knee miniscus surgery early in 1995 when I was 50. The accident happened a year before during an aftershock of the 1994 Los Angeles earthquake. It happened at my workplace so I got a worker's comp settlement out of it. The reason why I didn't have the surgery for a year is a long, uninteresting story. However, in that time my walking was really slow and I thought I was going to become a cripple for the rest of my life. Even during lap swimming, I couldn't even do flip turns because of the impact of the legs on the wall of the pool.
The surgery was a fast, in-and-out-of-the-hospital-in-less-than-eight-hours procedure. The first week was miserable: I was not used to being so dependent. Make sure you take your pain pills as ordered by the surgeon. I didn't at one point and paid with several hours of agony. I feel that I was a slow healer. It took me six months to feel really good, and about a year to be rid of all discomfort. A coworker of mine had the same surgery a couple of months after me. He was back to work after 2 days. For me it took a week. He felt totally well in three months. He is also 5 years older than me. So you never know how long.
Now for the good news. It was after that surgery that I learned to surf and started to cycle seriously. I never had and adverse feelings in the knee from even the toughest climbing in cycling. However, when I have a great day surfing, i.e. one in which I ride a lot of waves, I sometimes get some discomfort (nothing debilitating) where I had the surgery. This has to do with my stance on the board and how I maneuver it. All I can say is that the discomfort goes away quickly and does not stop me from paddling out the next day if the swell is still there.
Have the surgery ASAP and you will feel great in no time.