Getting older is not the most fun thing in the world, but the nice thing about aging is that things make a lot more sense to you than they did when you were young.

That said; I think the problem with a lot of older teachers can be a tendency to drone on, to tell anecdotes, to be arrogant...

All of which flies in the face of effective, accepted ESL teaching methods;

The less you drone on in class, the better your students will like you. Effective parwork use both saves wear and tear on the old voicebox, and spares students from a lot of boredom; it also keeps them focused on the tasks at hand, which are punctuated and affirmed by a teachers sparely chosen, well inserted comments and advice.

You've got to convince a prospective employer that he'll get good student feedback. Which an old guy can do, if he's a master of classroom management and can produce results.

Attitude is everything when it comes to aging.