So what is the earliest concert you can remember going to

I was there, too!

First show after moving to FL.
Houlihan stadium, or "The Big Sombrero".
If you saw a Top Banana (but mostly primer) 1970 Super Bee in the parking lot, that was me!

Michael Anthony broke the bridge (and therefore the strings) off his Bass while playing a solo and chugging what appeared to be an entire fifth of JD.

The last show I went to in OH was Motley Crue/Whitesnake/Anthrax.
Too cool. Yeah I had a '73 Charger at the time. Good time's.