Animisha Tara writes this blog in 2017, when her oldest child is 14 years old. She writes: "While my sense of pride wants me to point out that I don't actually fall into the category of "older adult", I'm not as young as I used to be, and clearly that makes a difference in how my memory processes function."
I find this to be a kind of hasty generalization, and here's why:
The study says that adults in a given age group, on average, given a certain level of commitment, tend to consolidate memory in a specific way.
Often, I find that in public talks/blogs, psychologists/neuroscientists start to give their own anecdotes. Like, we all feel like we've slowed down with age, haven't we? Etc.
But in science, one person's anecdote doesn't mean much. So I personally find this a little irresponsible on their part. Their personal experience has nothing to do with the study.
There is considerable variability in how different people's brains age. To take an extreme case, Arthur Rubinstein, for instance, seemed to retain his near-photographic memory until the day he died in his 90s. There are many people on these forums who have said that their memory in their 50s doesn't really feel slower or any different than it did in their 20s (they can still learn a concerto within a couple of weeks and so on), and I have met people in real life who have said the same.
Scientific studies "clump" all of this data, and artificially make it seem like the average is a "universal" facet of how humans work. I believe this is what keystring was alluding to as well.
And there are certain factors not being controlled for here: How much has the person in question tried to maintain her memory? How much does she actually use memory in her day-to-day? When looking at older adults, for instance, the idea that there tends to be some decline in memory function is rather "common knowledge". But we shouldn't confuse that to mean that there MUST be decline -- those are two different things.