I have been programming for over 30 years now. I've developed numerous applications and worked in several programming languages, operating systems and hardware platforms. Recently, I interviewed for a regular 9 to 5 with a startup company that vaguely seemed promising. I did an online chat that asked me a bunch of silly questions and a few programming questions. They liked my answers so they had me go to their office for an in person interview that took four hours. I haven't interviewed for a job in over 15 years.
I had to spend an hour with each of their 4 developers. The questions went from simple to hard. Throughout the process, I found it difficult to organize my thinking and it felt like someone had a gun to my head. The questions were very computer sciencey and you'd rarely encounter such problems in the real world. Nevertheless, they were somewhat simple like counting the nodes in a tree with any number of children and squaring a list of sorted integers while keeping it sorted.
I generally understood how to do it, but I struggled with the details and kept getting confused. As I worked through the problems, I couldn't recall the last step. I've always had problems with my working memory, but in this case I was exceptionally bad. I suspect that most of it is age related. Does age affect your programming ability?