A little while ago I was at a party en femme and met an older man who didn’t know many transgender people but was interested in talking about it. He mentioned someone else he knew who’d transitioned, and asked about how to refer to that person when discussing things they’d done together before the transition. He said that in that context it felt more natural to refer to them by their old name and pronouns. While I understood that, I responded “It’s considered polite to refer to someone who’s transitioned by their new name and pronouns, even when you’re talking about them before the transition.”

I stand by that response, and I think that that custom is quite appropriate. For most trans people, their new identity is important to them, they have gone to some struggle to reach it, and that’s how they prefer to be thought of in general; they’d prefer to turn the page on the chapter of their life where they had been called something else. So where there are not other major considerations that override, it’s generally polite and preferred to respect their wishes to be referred to by their new name and pronouns, even retrospectively. That norm seems to me extremely reasonable. What I disagree with is an emergent norm that goes much further than this.