First computer experience: having my name typed out on a piece of teletype paper, in code, when I was 6, at some kind of "open house" night at New England Telephone. (My mother worked in the Dial Bureau, the billing section). Little did I know that 13 years later I'd be working in that very same building as a long-distance operator.
First time on a keyboard: grade 10, when we had to write a program to solve a geometry equation. Don't ask me what language this was in or what kind of equipment I used: all I remember is (1) it took a lot longer than doing it longhand; (2) the keyboard, which was the size of a large electric typewriter mounted on a pedestal, was in one room, the printer, a teletype-looking machine, was in another, and (3) I kept forgetting to space properly, resulting in numerous "!" error messages. This experience so scarred me I wouldn't go near a computer for 15 years and have never made my peace with them. I routinely holler at mine, didn't even acquire an email account until 2000, and still use an old electric typewriter to compose snail mail correspondence. (Not much longer, unfortunately, as you can no longer get ribbon for the machine and several of the keys have lost their caps. I give the machine until the end of the year, if I don't use it much). I still consider email the bastard child of real correspondence, which by rights comes in an envelope and isn't so likely to be monitored by unwanted eyes.
First time on the Internet: 1997.
First post on a forum or message board: 2001, about the time I realized that technology was sweeping away everything I'd familiarized myself with up to that time. (I spent a lot of time in the woods, otherwise this epiphany would've occurred sooner).