As a young person, I can at least anecdotally say the same thing is happening to people who, while older, ain't old yet.
>>...and old too soon.
>>–Danish Proverb
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At early-forties, I don't think I count as "young" anymore.
Definitely: growing up without a cell phone was beautiful. I still remember driving around semi-lost, using paper maps, quite fondly (I still print directions).
My last partner (eight years my junior) "grew up on her cellphone" and it was just remarkable how fucked her brain was... at least different from my own landlined-childhood POV (e.g: attention-span; need for constant contact).
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And yet, my brain also enmushifies (lately: increasingly).
You won't catch me (nor any of my brilliant brothers) doing math without a calculator... and I got a SAT790Math way-back-when (do they still score that way? I missed one question, only; many of my brothers scored 750+).
if we get to live through the (forthcoming or already unfolding) singularity, there's a fair chance new life standards extend to 140-180 years*, with medicine, yoga, nootropics** and all.
* https://en.wikipedia.org/wiki/Life_expectancy#Maximum ** https://en.wikipedia.org/wiki/Nootropic