For me it was early 1995. (Can anyone beat that?)
I was using OS2/Warp on Windows 3.1
With every purchase of OS/2 they gave you an ibm.net email address.
Back then the WWW was in it's infancy, with most pages just being text.
Before 1995 I used to log into homemade BBS systems.
I'm guessing 1198. Back in the days we are only using dial-up.