I’m starting to wonder if many of us backyard chickeners are seeing our pullets laying earlier than what we usually see advised, maybe because they’re getting better nutrition and living conditions.Two are laying pullet eggs which shocked me because I expected it a month from now! One being the 18 week old and the oldest started when she was 20 weeks old. I thought they were called hens as soon as they laid their first egg. Wow, I'm surprised I've just gotten this much misinformation since I've read multiple chicken books, hachery pages, and other various sites for almost a year before getting my fluffy friends.
But meanwhile, as to what we find online, we’re seeing more and more the results of generative AI enthusiastically and erroneously scraping up random posts and presenting them as facts.

At any rate, you and I have definitely got some early layers.
I actually agree with you that they should be called hens when they start laying, but by convention, it’s when they turn a year old. If you can come up with a rough estimate of when they hatched, call that their birthday, or actually “Hen Day”!