Interesting question!
I sorta go back and forth about how important passing is to me. I think I will be content if I reach a point where I blend for the most part---close enough that people aren't clocking me in public very often. But I'm not really after stealth, and I don't plan to hide that I'm trans. I'd rather it not come up much, because honestly, it shouldn't matter.
I'm willing to transition without knowing that I'll pass for a few reasons. The cheap one is that I think I will be able to pass reasonably without too much effort, as I don't have an especially masculine body or facial structure. So that lessens my worry. But even if I don't pass, I know that I will feel better as myself. It'd be nice if people saw me as just another girl, but that's not critical to my happiness. I'm already pretty socially inactive (and I was even before the kids caused that), so it's not like staying in on Friday and Saturday nights would be a change.
But I think the main thing is that my goal isn't to pass, it's to be who I am. Cis women don't automatically get to be stunningly beautiful just because they have two X's, the majority probably wish they could change their appearance. It's sad, but society is not cruel only to trans women, it's cruel to women, period.