There is a kind of self-awareness that Descartes, the French Enlightenment philosopher expressed as "Cogito Ergo Sum" or "I think, therefore I am." In the philolosophy world, this phrase is called simply the Cogito for short, forms the basis for a whole school of thought called Rationalism, and is one of the few philosophical declarations that persists into common culture.
It's a springboard for self-examination and self-study wherein one ruminates upon one's own condition and place in the world. Based on a basic understanding each person exists as a discrete human being, separate from all others, it is the beginning of our understanding of what we call personhood now.
As one adds years, however, the nature of that awareness changes because, well, we change. Life begins by building and growing, but if one lives long enough, eventually evolves into shedding and simplifying. The skin is perfect mirror for these changes. When we are young, the skin can barely hold all that we are and do. It is fine and smooth and full of young oil.
Like a balloon, however, we can't possible continue to expand. Long lives accumulate too many experiences, too much knowledge and understanding, for young skin to contain and the strain of it is reflected there.
Skin
Accomplished adventure looking for release.
What is done is not left behind but carried,
Years less burden than welcome weight.
Gradual deconstruction remarks survival and triumph -
Allows accumulated pressures to fall away,
Disassembling their hidden gathered strength
Rather than preserving dangerous retention in visible beauty
Until skin can no longer contain it
And gives way in frantic cogito,
Imploding like a star.