I started smoking in 1985, and the legal smoking age at the time was 12. A year later, it went up to 13 and people were getting their middle school friends to buy for them. Didn’t really matter though, cigarette machines were everywhere.
I’ve never been a smoker, but there were plenty at my high school (class of '85) even though there was no designated smoking area. Smoking was officially banned but unofficially winked at behind the building or in the restrooms.
Also no shortage of smokers in my college and grad school years. Only later when I’d moved to Seattle and the city banned smoking in public buildings did I notice a decrease of smoke around me.