As a surgeon myself I can add a little to this topic…
The ACL tear is obviously a very common skiers injury and many people who tear it continue to enjoy skiing for a very long time. That statement includes both those who have repairs and those who dont, although I dont think that competitive or serious ski mountaineering is too advisable with a torn ACL which will allow significant pivot and travel in the knee joint.
If you’re an active person, I would have it repaired as the long term outcome is a reduction in the chance of arthritis in the joint.
In terms of timing of surgery, at the moment the knee will be full of blood from the tear. This will take many weeks to resolve and during this time the knee will be very stiff.
Surgery should not be contemplated until at least 3 months after injury, there are various operations with different pros and cons and surgeon preferences. Recovery after operation will be 6 months back to athletic standard - some elite athletes manage it in much less.
Anyway, there is a little overview which I hope is some help.
PS: I remember those little fences well, but with no fondness