Bhagavad Gita, Chapter 2, Verse 13

As are childhood, youth, and old age, in this body, to the embodied soul, so also is the attaining of another body. Calm souls are not deluded by this.

The body changes with age. The soul just changes bodies. Nothing to fear there.

You've already lived through earlier versions of yourself - the body you have now isn't the one you were born with. Death is the same kind of change, one more time.