You may be able to find the origin of this on a site called We Hunted the Mammoth. It’s a website that tracks activity and information from Manosphere websites on Reddit and 4Chan. From my reading and questions there I’m pretty certain this is while not a brand new stereotype, (there have always been some elements of the idea in the trope of the Old Maid) but it’s been resurrected and bruted around in those types of places where men who hate women hang out! One of their primary tenets seems to be the idea of The Wall. That all women over 25 have hit a fertility wall of some kind and are not good for sleeping with, or dating, and definitely not for marriage. They really love the idea that women over 25 are worthless in the “sexual marketplace”! (These are their words!)

Be careful visiting any of these sites (and maybe just access them through WHTM) because those same men regularly fantasize and advocate about physically harming adult women and the sexual assault of young girls.