TOD - the first concerts I remember attending were the ones my sister was in when she attended our high school 9 years ahead of me. There were winter and spring extravaganzas, featuring the entire music department. Also, in the spring, there was Band-o-rama, with the concert band, marching band, and jazz band, whose theme was Peter Gunn. My sister was in the vocal groups and I remember the big excitement when she had a solo, "Many a New Day," from OKLAHOMA. I learned a lot of concert etiquette from attending those events with my parents.
First professional pop concert was Peter, Paul, and Mary at Detroit's Masonic Auditorium. Went with a group of high school friends and felt very hip. At the same venue, I saw The Kingston Trio and Bette Midler on her first tour, with Barry Manilow as her pianist and Melissa Manchester as one of the Harlettes.