Understanding Authors' Purpose in Memoir Excerpt

Read the following excerpt from a fictional memoir:

"Growing up in a small town, the rhythm of life was dictated by the seasons. Spring heralded new beginnings, where laughter echoed through blooming fields, and yet, with the fall of autumn leaves came the reminder of time’s relentless passage. My father used to say, 'Life is but a series of moments; cherish each one, for they slip through your fingers like sand.' This mantra became a guiding principle for me, shaping not just my memories but my understanding of what it means to live fully."