It seems that I'm not alone in having started with a Commodore-64.
The first computer I ever actually used was a Sinclair ZX-80 that a teacher brought into primary school, and we were allowed to program in Sinclair BASIC with.
At secondary school we used strange Z-80 based Research Machines, RM-480Z I think, running a form of BBC BASIC and a Logo clone called Turtle.
My best friend got an early Commodore-64, and when my dad got an unexpected income tax refund, I got one too. I started with the C2N Datasette, but later upgraded to the Oceaninc OC-118N 5.25 floppy drive, which came with GEOS, the first windowing software I ever used - it was better and more functional that Windows 3.1 and Word 1.0 for Windows.
On the venerable 64 I played lots of games, many still available for the "VICE" emulator, learnt to program in the terrible Commodore V2 BASIC, then tried Basic Lightning which was much better, and finally 6502 assembly. I managed to create a hi-res printer driver for my Citizen-120D printer, which was rather fun.
The C64 is fully functional, and lives up in the loft, I really should dig it out when I get time one of these days!