Ask HN: Is it harder to code as you grow old?

My dad keeps telling me that I should stop being just a programmer and take more responsability, because according to him, when I will grow old, there will be younger better programmer out there, knowing the latest technologies, and I won't be able to keep up.

I have always been good at learning new languages / frameworks, but I see his point: when I work with older programmers, most of them are indeed a bit slower to adapt, and have a harder time learning new concepts (like Observables in Javascript).

But I am very happy with what I do now. I love being given technical challenges and solve them ; I don't want to manage teams or write documents about architecture. So I'm asking you, especially the senior developers out there: do you see yourself struggling to keep up as you grow older? Is staying "competitive" more challenging? Do you regret not taking more responsibility or do you still love being "just" a programmer?

Thank you all very much for your insights :)