First computer I got to see: Commodore PET 2001 (the one with the chiclet keyboard) - 1978/79 school year
First computer I had access to: Apple ][ - ca. 1982
First computer I owned: Commodore 64 - Christmas 1984
If we are making so many categories...
First computer I got to see: ca 1972, some kind of mainframe (IBM? ICL?) operating behind a large viewing window at L D Nathan in Auckland, while with my father while visiting his uncle who was a big shot there. Also my first time (and quite deliberately without prior explanation!) in an elevator.
First computer I touched: near tie, 1977, Commodore Pet in an office equipment shop in Whangarei, TRS-80 in the HQ of David Reid Electronics in Takapuna Auckland. I was a customer, having mail-ordered literally ten 7400-series ICs, 555, veroboard, soldering iron, wire from their huge catalogue with the distinctive Moire-pattern cover.
First computer I programmed (low level language): 1978, HP-97 calculator (mag card storage, printer). 26 registers, 224 bytes of program code. Owned by Tikipunga High School (not my HS, but nearby)
First computer I programmed (high level language): 1980, Burroughs B1700. My HS maths teacher had after-hours access to this machine in a bureau in Whangarei. He took our (hand) punched card FORTRAN decks there in the evenings, brought us printouts next day. Sometimes I (and one or two other students, but mostly me) accompanied him, enabling multiple debugging cycles for our (personal, more ambitious than the assigned task) programs. I got to put our HUGE 5 MB disk pack in the drive, enter the 1st stage bootstrap program into RAM using the console, use the TTY console and card punch machine. My teacher died in August this year, aged 99. I last visited him Nov '22.
First computer I had long term possession of (low level): 1979 TI57 calculator, mail ordered from the aforementioned Davred. 8 registers, 50 bytes of program code. No non-volatile memory. Most complex program I wrote on it (including working out the equations): Great Circle bearing and distance from one lat/long point to another.
First computer I had long term possession of (low level): 1980 Apple ][+. My HS bought it, the aforementioned maths HoD told me to take it home over xmas/ny, figure it out, and then teach him about it. Technically I wasn't a student there any more as it was after the end of term and exams.
First computer I owned: 1989, Apple Mac IIcx. I'd been using/programming Macs for years at work, and been able to take them home when desired, but I finally bought my own because Actrix BBS in Wellington offered shell accounts and UUCP and access to internet mail and "news" (usenet) which they themselves got via UUCP. And I bought a cheap (US$99?) Chinese non-approved 2400 bps modem at Macworld SF (before I had a computer). I also had been using BYTE magazine BIX bbs via X.25 at work, and continued using my work login from home. Maybe a year later both Actrix and BIX got TCP/IP connectivity and I could use the almost free telnet instead.