I would expect the effect of sex ed (real sex ed, not "abstinence and jesus") would be to decouple fertility and sex frequency.

In a place where abortion was legal, I expect having sex ed would not significantly affect fertility rate but would decrease abortion rate.

I expect fertility would drop, but frequency of sex would rise.

Knowing about your body and having access to contraceptives should in my opinion promote the frequency of sex.

I would expect it to reduce fertility because we know when you explain to girls how human reproduction actually works fewer of them are onboard because that sure looks like a traumatic experience. Oh so eventually after the other horrible side effects the parasite gets so large I have to push it out of my body through an orifice which is clearly not adequately sized for this purpose? Strong no.

But the other part sounds fun, so, why wouldn't learning about that encourage you? If you've done a decent sex ed course then a whole lot of fun possibilities are showcased, even if you think some of them are gross the others seem intriguing enough that I'd expect more rather than less will be interested in trying.