First off, its freakin' amazing that you can do an online search on your favorite band from back in the day and get a complete concert schedule from 50 + years ago. Simply amazing. With that in mind.....
My first concert was Steppenwolf, with an opening act of the Grass Roots. San Bernadino, California.
August 1968. Swing Auditorium in the First Annual Inland Empire Pop Festival.
I went with a Ms Love. My first "date". Her first "date". We were both gobsmacked with the spectacle of the 1960's in full bloom.
August 21, 1968 Swing Auditorium, San Bernardino, CA (First Annual Inland Empire Pop Festival, with The Grass Roots, Sonny Love, Sonny Knight & The Soul Congregation, Chicago Transit Authority, The Fabulous Wahler & Three Dog Night)