I left school 1990, single sex comprehensive, but a lot of 6th form subjects were shared with the boys school, and we'd known most of them since primary anyway - small town, rural catchment. Sex Ed focussed a lot on pregnancy (must ask one of the boys one day if theirs did too, or whether it was the focus for us, because we had the pregnancies) and STIs, especially HIV, so everything was condoms, becausewe were all goung to die of AIDS.
Except obviously it wasn't always condoms or any other contraception - there were 3 pregnancies I knew of in my 5th year (year 11 in new money.) One ended in a miscarriage, but the other two had their babies. And scandalously, a girl a few years below had a baby at 13.
It was cool if you had "done it", but not cool to sleep around. I did not get any opportunity to do it with anyone, and didn't even get a kiss. In 6th form, I did get a few drunken kisses at socials, but no one ever wanted to go out with me. I lost my virginity at 18 at uni. I never really cracked the social codes, but it was clear there was a fine line between being cool for having had sex and being a slag for sleeping around. I think the line could vary a bit, according to how cool you were perceived to be, and also whether it was with boyfriends you were officially going out with or one night stands.