Saying y/n parodies the old DOS programs people used back in the day. It means yes/no, and some geeks still use it when they ask questions.
For example:
A type of character in Wattpad fanfics and Gacha videos, and it stands for Your Name. Most of them have white skin are girls (and also demigirls), but some are boys(and also demiboys), enbies(and also demienbies and genderqueers), genderfluids, and so on. They are born without a name, so this is the reason why they are called Y/Ns.
Person A: Seriously?
Person B: What is it?
Person A: I'm trying to read this fanfic, and this stupid y/n keeps on stuttering and blushing "as hard as a tomato" and I'm not even white!
everyones getting it wrong. y/n may be a pick me, but it stands for YOUR NAME. so, whenever u say "y/n's a pick me" youre saying that your names a pick me.. y/n js means your name, mainly used in fic/wattpad stories