The special theory of relativity states that every mass in the universe has its own clock. I have one, you have one and our nearest star has one, so matter only has the same time if it has the same speed. General relativity lets gravity change matter time as well as speed. Time slows down near a large mass like the earth so a lot of computing is needed to make satellite navigation work because the internal clocks of GPS satellites far from earth tick at a different rate from the receivers on the ground. If one day people lived on the moon, time would pass faster for them, so they would age a tiny bit more because the gravity is less.
All this weirdness occurs because matter time passes when it complete quantum cycles. When large matter bodies like the earth spread their quantum processing around, they slow down the network which slows down time. Gravity slows time when the quantum field around matter makes quantum cycles take longer. The earth as a quantum aggregate superposes its existence on the quantum network around itself which alters how time passes around it. Gravity slows down time, as Einstein concluded, but does so by acting on the quantum network not on time itself. In quantum realism, time is a measurable property of our reality but it doesn’t exist in its own right.
Would one live longer on a larger planet that has more gravity? It might seem so to others but the quantum cycles one experienced would be the same. Living on a heavier planet stretches time relative to earth but it doesn’t change the amount of time one would experience.