Do you really think it would affect my performance that much? Would it affect all stair sets and coming off of, say, a 2 foot ledge/hubba?
I don't say you will never skate again, because that's bollocks. Also, you won't die from having an LL op (or let's say, the chances of you dying are as high or low as for any other operation).
You are probably a young dude, if you are still doing 10 stair sets. Why not enjoy that level of skating a couple of years more, until you are getting into other things in life a bit more which don't require such a high level of balance and foot/legs coordination. And then, do LL.
Even if you have a perfect recovery, which is certainly possible, whatever some people on this forum will tell you, you will still be out of skateboarding for at least a year and a half, in a time which might be your prime.
Do it, just do it a couple of years later.
You still have much time.