Since JAM hasn't gotten around to replying yet I'll take a swing at this. Age does have a whole lot to do with heart. Somewhere between 12 and 20 I think most people have the heart of a champion. They don't often have the skills to go with it but they have a huge heart. Quite a few competitors carry this into their mid-twenties or a little later. Somewhere between 25-35 the realities of life hit most people square between the eyes and they become realists. They can be very tough competitors and champions but they are no longer doing it on raw guts and belief in themselves. They are doing it on a careful realistic assessment of themselves and their opponents.
It is indeed a rare bird that has the heart of a teenager into their forties and beyond. I'm paraphrasing here, the basic story is true but I don't actually remember the player and details. A great old time baseball player was asked what he would hit against the modern pitchers. ".330"
That wasn't too far from his career average but the interviewer asked the player what would be his problem with the modern pitchers. "Would it be the speed they pitch at now, better breaking curve balls, what?"
"I'm sixty years old."
That is a great example of heart at any age. Few have it after the realities of life set in. That great, usually a little unrealistic view of yourself, causes many a crash and burn. Once in a rare occurrence, it leads to greatness and great accomplishments. I know that head beats heart almost always however someone with heart can never be counted out until the last ball falls because they are still trying to win and still a threat.
I greatly admire heart in someone who is old enough to understand the realities of life. I'll almost always bet head over heart though, that is where the money is most of the time.
Hu