The way she don’t know about sex is pretty resonable as an Asian. We never have sex-ed in school, parents be like “that adult stuff, kid get out” or so. We do learn about reproduction and stuff but the first time I awear of sex is in 9th grade from my classmates, after that everything else is from the internet (lucky that I didn’t go the wrong way). So yeah, if she is a good girl then no way she will know what sex is.
And about the story, not really enjoy it...and I won’t be that calm if I was her “-_-
Sorry if the English is bad.