100yrs? Seriously?
With diapers and all that?
Strange notion, as many who would wish for eternal life already get terribly bored on a rainy friday afternoon.
Guess it all depends on whether you believe in life before death.
And if you do, you should better live in the here and now, focus on what you consider important.

Do not worry. You will die.
We all will. It is the only thing we can be absolutely sure of.

A very close friend of mine got a terrible cancer diagnosis. A friend and medic had to tell her on the phone.
When she got the call, I stood next to her. I do not know much about cancer but the celltype was highly aggressive and the location of the tumours did not look good. Not at all. Too many lymph vessels affected, metastases were highly likely. It was more like a death sentence.

She retreated into a little cabin in the woods for two weeks, contemplating her life. And what of all the things she did now still had relevance. Keeping her tears and dispair to herself.
And coming back, she started to fight the cancer.
Accompanying some of her path was one of the greatest teachings, I received in my life.
Very high age?
She would laugh at this idea. It is not really relevant.

Just be prepared to die.
And then live as long, as fearless, useful and intensive as you can.
She does.
We will meet next week in London.