Well Grandma, my mother lost her marbles almost 38 years ago, right around the time I was born. At least that's what she tells me, although I suspect it was probably 2 years earlier, when my brother was born.
So I don't think it was age that did her in.
But one thing I have noticed with age, is her unwillingness to try new things. Her husband bought her 2 computers, but she wouldn't use them. He'd bring them home, she'd say "wow, thanks", and into the closet they'd go. It wasn't until I built her a PC, set it up at her house, and taught her how to use the email, that she gave it a chance. (Only because she'd feel guilty not to.)
Then I taught her how to surf the internet, and then I showed her how to print, etc. I used to get calls once a day with her screaming "my email disappeared", "why is the screen black", "it says I won something", "why is someone trying to sell me ......", etc. But now the calls are down to once a week, and she's loving talking to her friends, looking up recipes, and shopping online. (Well, she finds stuff that she wants to buy, then calls me to order it for her.)
So with e-cigs, I'll have to try the same strategy. First I'll find the perfect e-cig, then I'll bring it to her, then I'll show her how to use it, and then I'll check on her every day to make sure she's using it, and help her through any problems.
I am the heaviest smoker that she knows, (I smoke 3 for every 1 that she lights up), and the only other smoker in the family. If I get off the cigarettes, the pressure will be on her big time. She can either get on board, or suffer the incessant nagging of the rest of the family all alone.
If I don't frighten her away, and make it simple and easy, I'm sure she'll get on board.