I realize that I am guilty of ageism—and in particular, what I would call self-ageism. Ageism is a form of prejudice. It means thinking poorly of someone not because of their behavior or character, but simply because of their age.

This realization came to me the other day while I was considering the possibility of joining the board of a company doing work I believe is very important. I said to myself, “You can’t join the board because you’re too old.” This wasn’t because I doubted my ability to contribute, but because of how I thought others would perceive me.

Chronological age is not the same as biological age. Chronological age is useful in understanding the kinds of experiences a person may have had. For instance, I can remember when televisions were circular, the images were in black and white, and there were only three channels. But this says nothing about my biological age.

Biological age is complex. It’s an estimate of how you compare to others, physiologically. It’s often thought to follow a bell curve around chronological age, but I don’t believe that’s accurate anymore. Advances in healthcare have extended both health-span and life-span. Importantly, different parts of our bodies age at different rates, making it hard to define anyone by a single number. For a board member, cognitive function is far more important than the ability to lift weights.

Yet the world still runs on chronological age. For example, I can’t get a mortgage in Italy, where I now live, because of my age. No test of ability will change that. It’s understandable that things like life insurance or driver’s licenses must rely on averages, but I don’t think that should apply to things like board positions.

Intel, where I served as a corporate officer, had a policy that management board members had to retire at 65, and corporate officers could not be older than that. That included people like Gordon Moore, Andy Grove, and Les Vadasz. Outside independent directors could not be older than 72. This meant losing those with the greatest experience and wisdom. It didn’t seem to work out so well for Intel.

I believe I still have much to offer. I shouldn’t let my perception of how others might view me affect how I view myself. While ageism is real, I at least have control over how one person sees me—me!