I'd rather not skip the entire encounter in Act 1 just in case maybe something interesting happens in Act 3. I don't want spoilers, but I'd appreciate if anyone who didn't invade her lair at all in Act 1 chimed in if it changed anything. If nobody did, I guess I'll have to be the first, but i'd rather avoid doing it for nothing if possible.
I never skipped that encounter, but no matetr, what you do in act 1, you can decide everything new in act 3. You can fight her or not in act 1, doesn't change, that you can choose another way in act 3.