What we have here, is a closet masochistic pervert who got hooked into buff-dude fetish via erotica literature. Her sexual knowledge comes from the books she read. TLDR; She bled with our MC's HYPER WEAPON.
Ik It's kinda late as I've just started this but,what u mentioned does explain her having sexual knowledge but it still doesn’t explain why and how she compared mc's dick and said:"It's twice bigger than the ones I've seen".That's pretty sus.