My earliest recollection of seeing a live, electric rock and roll band is of a group I saw playing CCR covers while I was on a family vacation in 1969.
One year later I saw the original lineup of Cactus. I was at a summer "sleep away" camp, when one day the earth literally began to shake and our counselor told us that Vanilla Fudge had changed their name to Cactus and were using the campgrounds to rehearse for an upcoming tour. So we all walked over to where they were playing and watched them. Their PA had 48 speaker cabinets. I counted 'em.
First concert I ever actually bought a ticket for was Harry Chapin playing in my high school auditorium in 1975. Tickets were $3.00 and maybe 200 of the 1500 students in my school showed up. He had just had the #1 record in the country a few months before.
First "big" show was the Allman Brothers and the Marshall Tucker band in March 1976. It was at that show that I heard the guy sitting behind me say, "I hear Paul McCartney and Wings are gonna be here in a couple of months." My friend and I looked at one another and in unison we said, "We're going!"