I've recently come to realize that I'm trans. If I accidentally used the wrong pronouns when referring to myself (I used to use he/him pronouns and I'm having trouble correcting my habits) and someone else decided that gave them license to also use the wrong pronouns, I'd be pretty unhappy. I don't think there's ever a good excuse for using the wrong pronouns.

Own up to the mispronoun for the love of God. It's not that big of a deal.