You sound ridiculous because pronouns are just a normal part of speech which you have already demonstrated you use fluently. What you actually mean is that you hadn't encountered people specifying their preferred pronouns explicitly before. It's a thing you're most likely to encounter if you meet a trans/NB person where it's not entirely obvious from their presentation (especially online where you otherwise have a handle and a profile pic, both of which may be quite ambiguous. Women in tech are likely to do this even if not trans because of the strong tendency to assume male by default), or in spaces/from people who are trying to be inclusive of such (though, frankly, it's usually best dealt with a section in a bio or a badge. Even in the most queer spaces I've been in I don't think I've ever heard some say out loud "Hi, I'm X, pronouns foo/bar". Usually it's pretty obvious what they're going for, and if not, they'll have a badge or perhaps politely correct you if you assume wrong).