When your ACL broke, that took the strain instead of something else. Next time you have the same wreck or landing, the "something else" is going to break or get fatiqued.
So, no, you don't need the surgery. You can ride, jump, run, bike, etc. for many years and be happy. However, if you are committed to landing big loops and you know there will be some hard landings, get the surgery. You don't have to rush, but plan on it.
I don't currently have a right ACL. That was verified recently by an MRI, but I believe I tore it 20 years ago. It didn't become an issue until recently, but I did always feel it when riding fakey, on bad landings and occasionally when snowboarding rough conditions. I suspect muscle tone in other areas dropped and now I don't have the stability for certain riding styles, so I ride more strapless under the kite, and on snowboard don't really jump because the landings tweak it. Powder is not a problem.
Now, you are not getting it for the same reason I have been making excuses... you ride a board year 'round and don't want to be off it for the 3-6 months it will take to recover. The good news is, you're 20 and will heal fast and likely won't even notice the surgery in a few years. But if you are really throwing down, you'll likely break it again. So plan on two surgeries and after the second you'll become a world class foil border instead.