Internet:
The internet existed as far back as at least the 1970's but it was a strange land that only weirdo nerds inhabited up until the introduction of Netscape Navigator.
According to Wiki, Netscape Navigator came out on 12/15/1994 so I guess mine wasn't the last HS class before the internet, that would be the next class, the class of 1994.
Around the same time, AOL was gaining steam.
This is an anecdotal experience but I think it helps to illustrate the RAPID change.
During my sophomore year at Ohio State I was out with a group of guys who were in my calls (all Sophomores who had graduated HS in 1993). We got invited to go visit a friend of mine (female but not a g/f) who had graduated HS a year behind me. When we got over there, she and her friends (all freshman, 1994 HS grads) were all in some AOL Chatroom. We (spohomores) had literally no freaking idea what AOL, the internet, or a chatroom were. The ONE YEAR YOUNGER girls had to explain it to us as if they had just landed in a rocket ship. We found it creepy.
We (sophmores) had no interest and just wanted to go out to some bars. It amazes me looking back that this was just completely foreign to 93 HS Grads and seemed as normal could be to people literally only one year younger.