Your First Concert was.....

Steppenwolf at the War Memorial in Syracuse NY in 1968.--Mrmitch

Wagner Walkure, Seattle Opera 1974. The next year the whole Ring in english and German, then the next year as part of Sigfried, manually operating Fafner the Dragon.

But my first concert of the sort you're talking about was Talking Heads (and some video thing) at the Mudd Club, NYC 1978. My most fun concert was standing right in front of the Gang of Four (spring of 1980) in a tiny U.C Davis cafeteria side-room.

Gregg

The Beatles, Cleveland Municipal Stadium, August 14, 1966. I was 12 and went with my brother's friends. My next concert was five months later....The Monkees, Jan 15, 1967,Cleveland Public Auditorium!! (Not my brother and friends this time; me and two neighbors) Both were scream fests and I could barely see them.....BUT...I was there.

Jimi Hendrix - 1968 Will Rogers Collisium

Ted Nugent 198something in Albaqurque NM. with uria heap
....but my most favorite concert of all time was Jimmy Buffet alpine valley wisconsin 199something. It was a giant keg party and all parrot heads are cool cool. THey fed me burgers and they drank my margaritas. Just a whole lotta fun.