Not an Apology

Apologizing for misgendering a person isn't an apology, it's just an excuse for being inconsiderate and insensitive and not asking in the first place. You can always use gender neutral words to describe someone if you don't know or didn't have a chance to ask, but apologizing later for not using appropriate words, especially pronouns, doesn't change the original mistake. It does, however, give you the opportunity to learn so it doesn't happen again.