Not your size or shape, but the fact that you were once tinier than the period at the end of this sentence. Or the truth that you are one of almost 8 billion people on the planet today. Or the mind-boggling statistic that you are among over 100 billion humans who have ever lived.

Each of us – no matter our age or accomplishment – is only a small speck in the span of the universe. Yet we are beloved by our Creator, known and cherished by God who gave us life from the moment of our conception.

What does it mean that we all start small?

For seven years, I had the joy of taking part in a theological seminar on vocation across the lifespan. With an interdisciplinary group of scholars, we studied each phase of human development, from infancy through the elder years, to explore how God calls us at each stage of life.

During our meeting on childhood, I was pregnant and parenting two children. Yet I laughed with the delight of discovery when the theologian seated next to me started the meeting by saying, "This may seem obvious, but children are small! That matters."

Children's small size is the first reason we need families. Despite being a mother of many small children (and a child myself before that), I never pondered this truth until I read Maria Montessori's reflections in her essay "God and the Child":

"Let us imagine for a while that the world consisted only of adults, because man was born already developed and mature; and because of this could dispense with parents.

"The most basic community, the family, which of all natural communities exerts a deeper and more lasting influence on the spirit of man, and which sets itself up both by means of, and because of the child with his many needs, would then have no more reason to exist."

Humans could have been created to start life as full-grown adults: strong, smart and independent. Instead, God designed us as the utter opposite: small, weak and needy. God loves to start small.

I believe that matters. As adults, we are called to reorient our lives around the smallest ones in greatest need of our care.

For the past two years, I have been training as a catechist in the Catechesis of the Good Shepherd. This approach to faith formation teaches adults the importance of honoring the youngest children's existing relationship with God. It also invites us to see how God is always working through what looks small: people, places and actions that work toward the coming of the kingdom, no matter how miniscule.

Jesus started his earthly life as an embryo. Bethlehem was a tiny town in the backwaters. Our own faith can feel like a mustard seed or a pinch of leaven. But God cares about one wandering sheep, one lost coin and one precious pearl.

Look what happens when a single seed falls to the ground and dies, Jesus told his friends. It bears great fruit, bringing forth wild abundance from the humblest beginning.

Two microscopic cells once combined to become you. You are one of the grains of sand promised to Abraham, one of billions of stars shown to our ancestor in the night sky thousands of years ago. But together – children and adults – we become bright lights in the darkness, each of us part of God's kingdom.

If you feel too small or insignificant to make a difference, fear not. If you long to teach the youngest ones in your life about the vast mysteries of faith, don't be daunted.

This is exactly how God loves to start: small.

Fanucci is a writer, speaker, and author of several books including "Everyday Sacrament: The Messy Grace of Parenting." Her work can be found at laurakellyfanucci.com.