I remember the first time my neighbor came over and played The Wall on my record player. I was in 6th grade. What an introduction, especially in a household where the elders held on to classical and old jazz standards with tight controls. Yes, I heard of the Beatles, the Stones, Led Zeppelin, etc., but holy smokes! The order of my exploration was exactly out of order, almost random after that, slow. Next, during high school, Dark Side of the Moon, still on the Billboard charts even then, supposedly.
And then a flood: Piper at the Gates of Dawn, Meddle, Wish You Were Here, and all the others in between! The gates were open to a sonic awakening. Oh, to discover this was like discovering a secret that was in front of everyone, but only those in tune could see/hear it.