One starts to get young at ...

One starts to get young at the age of sixty and then it is too late.
One starts to get young at the age of sixty and then it is too late.

More phrases

Courage - a perfect sensibility of the measure of danger, and a mental willingness to endure it.
 William Tecumseh Sherman
The same mentality that leads to environmental despoliation, environmental destruction, also leads to damage to people.
 Naomi Oreskes
You can't break poor people mentality. Once you grow up poor, you don't take anything for granted. It can have the negative side also because you can never truly be relaxed.
 Will Smith
The man with the average mentality, but with control, with a definite goal, and a clear conception of how it can be gained, and above all, with the power of application and labor, wins in the end.
 William Howard Taft
I think society had to grow up to the mentality of Peter Norman.
 John Carlos

Quotes from the same author

Computers are useless. They can only give you answers.
Everything you can imagine is real.
Only put off until tomorrow what you are willing to die having left undone.
I begin with an idea and then it becomes something else.
I am always doing that which I cannot do, in order that I may learn how to do it.