Unless an older person has some cognitive issues, learning one’s way around IT has to do with need and interest rather than age.
If one doesn’t require using modern technology in their day-to-day life, they might feel they have no need to learn it.
Or they’re like my dad, who was a mechanical engineer and loved all sorts of gadgetry. He must have been at least 65 when the computer age really took off but he learned his way around it all quickly because he was interested.
I know people in their 20s who don’t use smart phones and don’t have the need or interest to be computer savvy.