https://hahaquotes.com/quotes-on-wisdom-and-knowledge-humour-experience-life-age/
Several times over the course of my life I've caught myself thinking "I'm smarter than I was a couple years ago." Or "I can understand more than I ever have before." But after thinking that over, I realize that's not completely true. Sure I've learned more about the world we live in, I can tell you several things that I couldn't when I was younger. Like gravity pulls things down because the mass of the bends the space around the planet in a way that it makes things head down naturally when they get to close to it. But at the same time, there are things I have been told I could do when I was younger or knew the answer to when I was younger that I don't remember how I did it now. Like my parents have told me that through the earlier years of elementary school, I was absolutely amazing at math. They could ask me to solve a problem, and as long as I knew how the problem worked (addition, subtraction, multiplication) I could solve the problem almost immediately, even if the numbers got larger. But then I was taught estimation and that skill vanished.
This brings me to my thought on what happens as you age. Its not that we always get wiser as we grow older, what we do, is we experience things, and the more experiences we have on a certain thing, or the more important the experience is to us, the more we trust whatever we learned through that particular experience. For instance, I was amazing at math, but whoever taught me estimation was a teacher, and I was at the age where I trusted the teachers to know what they were doing better than I did. So if they told me whatever way I was arriving at the answer was wrong, even if it got me the same answer, I would trust them to know what they were talking about and decide to forget however I was doing it before. So I would lose the skills at math that my parents thought were amazing.
This is included in my experience because of a few things. As you age, you gain more experience, and one of the things that, as a society, we make sure you have a lot of experience in is how to explain your ideas in a way that other people can agree with and understand. Also, the loss of energy and way longer time being alive can build up patience better than almost anything else can. Finally, as people grow up they usually spend much less time with the 'elderly' leading to the older generations appreciating whatever time they have with people to talk to, (this can also lead to long rambles from trying to extend your time with other people as long as possible) so they try to help them by sharing their views on the situation. This usually end up leading to someone who is older proving to be quite wise to those they decide to share with.
As I mentioned earlier in this post though, as you grow older, you will forget things that helped you reach where you are today. I can't think of a way not to. After all, some experiences will tell you completely contradictory things, and you will have to chose which one to believe in. After this happens enough times you usually have quite a bit of evidence supporting what you believe in. Which can lead to some pretty polarizing opinions that are hard to get rid of. This was why I chose the image and quote with Einsteins picture up at the start of my post. Because science itself is all about proving things right, by proving other things wrong. Like when scientists proved that vermin (mainly) were not produced by specific types of food being wasted, contrary to popular opinion, by figuring out exactly what maggots life cycles were like and how they got into food containers.
There is nothing in life that we can say is an absolute fact. When we are younger, we know less about the world, but we are more adaptable, because we don't have all this information in our head telling us that 'you have to do things this one way' So we can explore more new possibilities. But as we age, we use our experiences to start to gain a belief that they are true we never question. If we lose our ability to question, we become as intelligent as other apes. After all we can teach some species of apes sign language (Koko the gorilla is the one I have heard about) but they never ask questions. If we stop questioning our own beliefs and experiences, we will stop advancing as a species. Which brings me to the Einstein quote and my opinion on it. Learn from experience, Live in the moment, and work for a better tomorrow. But we'll never have it if we don't question things.