My main online banking account is from 1998. Have another cluster of accounts from 1999, things like eBay & Amazon. Have a domain name, and thus email, that also dates to 1999.
I was recently able to recover an old Ultima Online account from 1997, but that feels like cheating here.
Wow, I'm surprised at the banking account from 1998. That happened rather quickly given that the web wasn't really on anyone's radar until 95/96 or so.
It was brand new at the time. I remember thinking it was super cool that it existed at all. They also had a tele-banking service you could still use at the time.
The UI has only changed notably 2-3 times in that time period too, although at this point 99% of the time I use my smartphone app to access.
I was recently able to recover an old Ultima Online account from 1997, but that feels like cheating here.