I teach undergraduate students. It works if you share with a sense of humor. It also works better if your story is not " We never had email", but instead your story is a funny or interesting anecdote in which the lack of email plays a part.
What do you care if they think you're an old geezer? You must have had something going for you to get to the age where you are. Let's see if they can do as well.
The "old geezer" view would be that of someone too rude to engage with, but I'd be perfectly happy to talk about pre-"device" days with someone genuinely interested.
The other day I was chatting to friend only a few years younger than me about our respective Christmas and New Year's Eve plans. We agreed we're no longer ones for spending a few hours standing in an over-crowded pub just to see the New Year in, and my mate said something like, "We're both becoming a pair of grumpy old men, like Victor Meldrew!"
{For those unfamiliar, Victor Meldrew was the leading character in the BBC-TV sit-com One Foot In The Grave; a humorous but sympathetic study of an elderly man who, despite evident good education and intelligence in his un-stated background, found many aspects of modern life very hard to manage, ranging from poor courtesy to the difficulties of obtaining proper service from shops, utility-companies etc. And you don't need to be a GOM to meet these problems, either!}
Benedict Arnold 