The oldest would be when I was about 4 or 5 years old, at my aunt's place. My best guess would be it was a Philips Videopac G7000. I remember being confused... Not fun, can we watch cartoons instead.
Pit Stop on Atari is the first console game I can remember playing at a friend's house, it wasn't fun either. Waiting for your turn, then not knowing how to operate it, crash and pass on the controller.
The first game I sort of enjoyed was Space Invaders in the canteen at sports. But mostly watch others play, then suck at it.
At the time we also had one of the first PCs, the game I remember playing first on that is Alley Cat.
Experience was, this is ugly, but kinda fun. No clue what I was doing though. Still don't know what the goal of that game was haha.
MSX got me into gaming though, Konami / Athletic Land
That felt magical, music, colors, responsive, clear goals.