Just for the record, the whole American thing of not referring to 'years/forms' at school as junior, freshman, senior (I don't even know if that's the right order) is confusing as HELL.
My experience is kinda strange and atypical- I grew up in a small town in provincial New Zealand- growing up in rural British Columbia or the Deep South of the USA would be comparable. I did not grow up on a farm, but I was surrounded by farms- farmers here are RICH RICH RICH, I'm pretty white trash. However, I was expelled from school at 13, at like 16 drifted to the nearest provincial city which happened to have a university, thus a small drug scene.
3rd Form/Year 7- Alcohol. Kids who had older siblings/parents who smoked weed would typically have tried weed by year 7.
4th Form/Year 8- Alcohol, weed more common, first experiences with codeine & morphine.
5th Form/Year 9- LSD, shrooms, mescaline.
And really that was it, there wasn't really anything else to take. I suppose Ritalin and benzos, but speed wasn't a thing back then, heroin didn't make it to my part of the country, prescription amphetamines were being phased out before I was around, ketamine wasn't a thing. I suppose I did get really into shrooming- when I was 17 (year 12) me and a couple of friends managed to collect ~3.5kg of shrooms over one season, kept them in the freezer in a shopping bag. Eventually when we were being kicked out of that flat we had to sacrifice the freezer, thus get rid of ~1kg of shrooms. So we had a huge party and fed them to everyone, but there was still a good 500g left...so (now) one of my oldest friends decided to try to eat them, he ate at least 2/3...he tripped balls for nearly 2 days...yes, he does have mild HPPD, thanks for asking
Alcohol and weed really are the mainstays though- I'd say 75-85% of people only ever 'got high' off alcohol and weed. Even if they were around, most people had no interest in taking Acid even if they could get it. The antidrug thing was pretty strong back then too, New Zealand is always like 5-10 years behind Europe/US.