I'm not sure how old you are but I remember using the internet back when they had BBS's.  I really enjoy what it has evolved into.  How about you?
I do not start to use the internet early but the fact that some interconnected computer networks that use the Internet protocol suite (TCP/IP) to link devices worldwide can send and receive information is a breakthrough. 
I agree - quite a break through for humans.  They finally had a spot to exchange information instantaneously.  It's interesting to think about days before it was widespread.  What did people do with their free time?
I love the working principle of  computer network. The use of  nodes to share resources.