My first time at a Major League Baseball game was at Crosley field in Cincinnati. I was around 10 years old at the time, a baseball fan, used to listen to the Reds games on my transistor radio (remember those?), and just seeing the size of the stadium, the crowd, the lights (it was a night game), it was quite an experience for a 10 year old.
I went down the the railing by the Reds dugout, joined the other 30 or so kids there yelling for autographs, I got Johnny Bench and I think it was Gary Nolan's autographs on the game program. Kept that program for years, but unfortunately they were in pencil and they faded away to nothing.
We were living in Dayton Ohio at the time and coincidentally that was when the Dayton Flyers made it to the finals in the NCAA tourney only to be crushed by UCLA where Lew Alcindor was playing at the time. Used to listen to those games on my radio too.
Another Dayton sports memory is sitting cross legged in front of the black and white TV and watching Bart Starr sneak in for the TD in the "Ice Bowl".