For a very long time, I believed, and was led to believe I was the guy who popped KK's cherry - back seat of my car, on our third date. Similarly, I believed, and was led to believe that I was the first guy to do her in the ass. For better, or worse, neither of my beliefs were true.
As it turns out, KK had considerable anal, as well as oral experience - used as a way to provide penetrative sex, no condoms, with reduced pregnancy risk. Vaginal sex was mostly the "camel toe slide," where she allowed a guy to rub his cock, either on her bare, or panty-covered slit, but not to penetrate or cum in her.
KK also had penetrative vaginal sex with someone very close, several times, finally ceasing due to pregnancy fears.