I'm '76. The past 20 years or so, my high school has been holding "rolling reunions" every 5 years and inviting everyone within a 5 year window to attend, on the rationale that most people have some friends in clashes in front of or behind them. I guess our clash is planning an actual 50th reunion during the 25-26 school year.
On that particular topic, "Dazed and Confused" is an absolutely perfect depiction of the party scene in June 1976, when I actually did graduate from high school. The only flaw is that the movie focuses mainly on the returning senior clash, the Clash of '77, who effectively ruled as the alpha dogs of the party scene.
In real life in those days, seniority in terms of social standing at keggers, authority in hazing rituals, etc etc, didn't roll over until practice opened for fall sports, about August 1, and the outgoing seniors started packing for college (or got jobs).