At age 70, I can tell I am not as sharp as I once was. I took the GRE a few years ago and scored 1280. Not a bad score but I once would have done much better.
Probably did as well on verbal as ever but when I got to the math portion, I kept coming across problems that as soon as I saw them, I knew that I knew how to solve them but when I tried to, could not remember how. Math was always my strong point too.
One of my best friends is president of Mensa for a large area. He has tried to get me to join but I am not certain that I could pass the test now. When younger I nearly always would score 99th percentile on achievement tests.
You seem to have the humble gene. That is good in my mind.
It’s not so much what one knows, but what they are open to learn...as long as logic applies.
As we age what we lose in IQ which is essentially a measurement of processing speed and ability to manage abstractions, we gain in Wisdom.