I tore my ACL 2 years ago.
Had surgery in Feb, a couple weeks after I did it. The doc strung it tight for me, so PT was a bitch, but everything was going great till about May, when we realized there may be something wrong. Turns out I had so much scar tissue that I couldn't ever physically get my ROM back, which made PT absolutely excruciating.
Had another surgery in August to get rid of the scar tissue (the graft was all good and healing well). Hit PT hard, and got done just in time for the snow to fall.
However, this fucked me because I wasn't able to get back into the gym at all. Went into the season super weak. So the first piece of advice is to get that ROM back, and get on a bike right away and ride it hard, every day. Get on a road or road-ish bike if you can, MTB can put more stress on your knee and make it painful. As soon as you are cleared, lift. Do squats and leg presses to build up your quads and muscles around your knee.
So, expect to feel a little weaker. It's not like getting back on skis after the summer, it's like rebuilding your muscle mass and then re-training new muscles to get used to skiing.
Second thing - You may find yourself with a mental block. Some people don't have this problem, but I really did.
I blew mine spinning a jump into choppy Pow. It took me half the season to get used to spinning medium sized park jumps again, the first three I did was such an adrenaline rush that I ended my day on it. It was like re-learning it, but worse... thinking about spinning got me feeling really shaky and anxious. It didn't bother me hitting rails or charging or spinning onto things, even nosebutter 3s and little 3s with bonks in the middle were fine.
I wasn't able to bring myself spin a jump into pow until this season (second since the injury) but I finished this season out skiing harder than I ever have in my life, so I feel pretty good now. I forget that anything ever happened until it's sore at the end of the day, or when I try to stand up straight because I can't straighten it all the way anymore. Scar tissue prevents me from getting back full ROM.
Bottom line, do your PT, hit the gym hard, and you'll be fine. Everyone says that to you, but you have to really hear it, want it, and take it to heart because PT is going to start to feel like a never-ending process.