[YZF]

I disagree.

The way I like to look at it is that you simply need to work a little harder. You see athletes in their 30's and 40's (and even much later) doing things that most people can't do in their teens. Why is that? It's because pretty much everyone is so far from their potential.

In theory some particular aspect of you may start declining but almost always this means that if you work harder at it you can outperform your younger self... So while there are some biological processes at work most of it is in your mind.