Not into? Anime, furry, teacher/student, school girl, pedophilia or age play, diaper, scat play, medical play/torture, etc.

I guess if it gives me a funny feeling down there or make me want to masturbate, or if the sex scene is incredibly graphic or BDSM, then it's likely erotica. Romance with sex tends to lightly touch the sex scenes or imply without going too into it, not too graphic.