And if you want to make it easier, I think you should target a specific group of old people. If you will randomly get old people just to tell them about btc, it will somehow be hard. Try targeting old people who live their life around the aspect of money, banking, investments, stocks, technology etc. They will be interested about it as long as you are good in explaining. But of course you can still try other group of old people specially those who are not even aware of the technologies we have right now. Goodluck with that OP.
There are only a small percentage of old people that are in the banking sector or in finance and most of them would be knowing what is bitcoin but they have spent their entire lives doing transactions in fiat and now they would not be as flexible like a new comer adult in the same industry, just have a look at Warren Buffet, he don't want to indulge in bitcoin maybe because he doesn't like that much volatility and want to play safe with his billions of dollars now in his old age, I guess it will be better to make the adults understand about bitcoins and also the children, they are the future of the world.
People are individually unique. We cannot see the level of enjoyment and awareness of the people when they are using technology. Maybe, this is easy to other specially those who had education but there are older people who can't take any changes. I think we cannot force them to know all about cryptocurrency because it might just end their lives. Sharing only about btc is a good way for them not to be ignorance. After all, the dedication they will put in order to know is their liability.