I had previously sat at the table and watched my older cousins playing in the late 70's, using the '74 three booklets, greyhawk, blackmoor, and Eldritch Wizardry, in JG's CSIO setting.
Got the Red Box in '81 and have played ever since (I still have the red books and dice from the red box though the box is no more). Unfortunately, I've not played since January as I can't find a group where our schedules mesh well. I love being a daddy now but it may be the death of my gaming (at least until he is old enough to play).
I started in June (or July) of 1981. The first time I actually played we did so in a tent, by the light of an oil lantern. It was great, and I've been hooked ever since.
Summer of '89 if I remember correctly. I caught the tail end of 1rst edition and then took off like a bat out of hell once 2nd came out. That was a great summer...