That would have been Slackware, which in those days came on a stack of 3.5" floppy disks. So early 90’s (and hence I was in my mid-30s) but I was still mainly using Windows 3.1 and Trumpet Winsock to connect to the Internet.
I think the first time I really took it seriously was in the mid 90’s with Debian, a copy of which was posted to me, on CD-ROM I think, by Ian Murdock himself (back in the days when he was still with Debra 😏).
Tusky for client. Lots of good medium sized instances (avoid mastodon.social). I’m on mas.to for a general account and mastodon.scot for a local one (both reliable, run by the same person).