Just a thought on a different angle. My CPL/IR instructor was 69 years old, a retired military and then retired airline pilot. Obviously he had thousands of hours of multi faceted flight experience, and was also a CAA CPL examiner. Before him I had one or two younger instructors, and I am not saying they were bad, not at all, but they weren't as good, either, as him.
I can safely say that I learned more from my retired-airline-pilot-turned-instructor than was required in any book, and more about real world flying which is probably more important than passing the tests, which he got me through anyway. I don't mind admitting I am no ace pilot, and certainly was a poor student, but with a steady hand of experience teaching me I reckon I am ok now, certainly I am a safe pilot. Not to mention the fact that when we had a problem with the landing gear tsking off for one lesson (turned out to be nothing more than a display problem, but at 1000 feet, well you just aren't 100% sure are you?) he took it all in his stride, did everything which could be done, took control and landed lightly just in case. No drama except for the red lorries chasing us down the runway.
If I make it to 69 and am half as good a pilot as he, I'll pass a little knowledge and experience on, I'll try and remember this thread, and hopefully retire fat and happy.