There’s a saying in English: You can’t teach an old dog new tricks. I think it depends on the motivation of the dog and the nature of the trick.
This young woman started learning to play the violin as an adult. See how far she gets in just a couple of years. Motivation and perseverance, right?
I looked up a Japanese proverb similar to “You can’t teach an old dog new tricks” and I found 老い木は曲がらぬ, which apparently refers to the stubborn nature of many old people and the idea that if you want to learn something or change yourself in some way, it’s best to do it while you’re young. But I’m told that’s not a commonly known saying. Can you think of another?