The foundation of Taylor Swift's fanbase has always been white Millennial women, whether they were in their teens during her "Speak Now" era or in their 30s for "Life of a Showgirl" today. And her lyrics have always reflected life at her age at the time (as well as the age of most of her fans).
She grew up and they grew up right alongside her with the same trials and tribulations. One reason she's enjoyed such loyalty and longevity.
Yes it surprised me last year as I observed the crowds on lower broad here
I expected teenyboppers