We were cross-town rivals, then. David Lee Roth attended my high school (John Muir, also in Pasadena) three years ahead of me.
Here's my Van Halen story. In my last year of high school, one of my friends was a budding rock guitarist. He often talked about the local band Van Halen and what a great guitarist Eddie was. Van Halen was scheduled to play a show in the Pasadena Civic Auditorium on January 25, 1975—thank you for the date, Wikipedia [0]—and my friend and I went together to the Berry & Grassmueck music store on Colorado Boulevard to buy tickets. At the counter, my friend said something like "I’m really psyched! We're going to get to see Van Halen! He’s great!,” and a fellow standing nearby perked up. After we left the store, my friend told me, “That was Eddie Van Halen!” Just hanging out in the local music store, apparently.
My main recollection of the show is that it was extremely loud: several stacks of Marshall amps in a concrete-lined exhibition hall and only a couple hundred people scattered around the floor to absorb the sound. I wore earplugs, but my ears still rang afterwards.
I see now that the next day was Eddie's twentieth birthday [1].