We see our bodies aging in the mirror, but we ourselves do not feel that we are older.
That is because your body is aging and your body exists in time. But the one who witnesses the aging body is awareness itself, and that does not exist in time.
As you sit in meditation, you become more and more the witness of experience (the one who knows, who is aware), and not the experiencer who is ever reacting to ever changing sensations.
The wise one witnesses in awe as life renews itself in every moment.
(1) These ideas are indirectly quoted from Jack Kornfield in a recent dharma talk -
(2) In TM, this "witness/awareness" is known as "transcendental consciousness", and the regular practice of TM is intended to awaken that consciousness so it is ever present, not only during meditation, but in our waking and sleeping states, as well.