1987 at seven years old. Dad bought me an Atari ST. It came with a Language Disc, containing the ST Basic program. Didn't know what it was, but dad learned from the guy in the shop it was for making your own programs.

So along with a manual, together we wrote our first program:

10 PRINT "ST";
20 GOTO 10
RUN

In the corner window, the results unravelled. I was so excited. Never looked back.