I'm 18, bout to be 19. I started when I was like 3-4 playing on my dad's old NES playing Duck Hunt and Mario Bros and the original Ninja Gaiden. But MY first system was the N64 when I was like 6 or 7ish. I've played on consoles since then. My first computer game was Civilization 3 and then I got Morrowind. Then I upgraded and bought Civ 4 (Obviously I'm not a big PC gamer)
I'm 29, and I started playing at age 3. Pong on the Commodore Vic-20 with my dad. Might've been slightly earlier than 3, but I remember playing at 3.
I've got a 3-year old son, and he games with me. Keep the heritage going!