I grew up near her and have heard the same things from people that went to high school with her but I always take it with a grain of salt. People want to rewrite history and think it gives them some small claim to fame if they say a superstar was mean to them.
Taylor Swift is the classic covert narcissist ruled by psychopath tendencies. No wonder she behaves like that and then turns things around when it goes sour and plays the victim. Probably her privileged up bringing didn't help much too.