Grow up, become more mature, become more alert and aware. And old age is the last opportunity given to you: before death comes, prepare. And how does one prepare for death? By becoming more meditative.
If some lurking desires are still there, and the body is getting old and the body is not capable of fulfilling those desires, don't be worried. Meditate over those desires, watch, be aware. Just by being aware and watchful and alert, those desires and the energy contained in them can be transmuted. But before death comes, be free of all desires.
When I say be free of all desires I simply mean be free of all objects of desires. Then there is a pure longing. That pure longing is divine, that pure longing is God. Then there is pure creativity with no object, with no address, with no direction, with no destination -- just pure energy, a pool of energy, going nowhere. That's what buddhahood is. Atisha calls it bodhichitta, buddha consciousness.
-Rajneesh