I have commented elsewhere already, but I think it's good to correct people when you know someone's pronouns are different to what was just used.

I am cis, but I am in community with many trans people, and am pretty good at remembering and using the right pronouns for folks. However, I wasn't always like that — I only found my queer community once I got to university, and I remember that I would often slip up when talking about an nb friend (who was actually the first person I met who used they/them pronouns).

I only got good at using the correct pronouns because of the support of friends who would firmly but non-judgmentally correct me whenever I messed up (and explain to me that I shouldn't make a big deal apologising if I did make a mistake).

My friends doing this helped me to get good at this much sooner, as well as shielding my NB friend from the emotional stress of correcting me; They once snapped at me when I slipped up, and later apologised and said that whilst they felt they were reasonable to correct me, that the anger they expressed was not deserved, and that it was basically overflow anger from having to deal with university bureaucrats and ignorant students who were not even trying to get it right. My point here is that I was a good faith person who was genuinely trying to be better, but my mistakes that occurred in front of my nb friend risked triggering a lot of stressy-upsetty feelings relating to being intentionally or callously misgendered).