Because of my age I am not familiar with the expression cool. My kids use the word and I must say it sounds funny. So I had to google a bit and I found out that the only way for me to be cool is to serve me on the rocks. Lower my body temperature and I am cool. So everybody can be cool, independent of his age.
But it seems that I can be cool in the view of others. I think they mean that I am an interesting man. That is a personal interpretation.
Being old is not a special achievement. It mainly means that your body did not decide to die earlier. But the things you collected in your brain are of special value. They could help people who start to walk the road that for the elder, who is near the finish, is a well-known way.
Yesterday I read an article from a priest who mentioned how wrong it is to exclude old people from social life. Not only for them, because of their possible loneliness, but also for the younger people. The wisdom of the elder can help the youngsters so much in their lives.
I talk a lot with youngsters. The generation of the computer games. They know that I am not interested in that stuff. But they are really bewildered when they hear that this quiet rather old man actually fired a real rocket (missile) himself in the mid sixties of the last century. And that I played the precursor of all modern war games. In those days you needed a container of 3 by 6 meters, completely filled with electronics, manned by two specialists and cooled by an enormous cooling system to support this game.
It suddenly makes me interesting for them and it helps them to understand that their world will be completely different when they reach my age.