I search the sea of wiggly bodies for a familiar set of eyes. When he sees me walking toward his class, his face lights up. He says goodbye to his teacher, and quickly closes the distance between us. He wraps his growing arms around my waist and gives me a tight squeeze. I bend down and place a gentle kiss on the top of his head. We walk hand in hand down the sidewalk, and he tells me stories while we wait for his older brother. This after school ritual has become one of my favorite parts of the day.

My youngest is just a few short weeks away from finishing kindergarten. I know as he continues to grow, his excitement over something as simple as his mama picking him up from school will lessen. He won’t always be so eager to show me affection in public, to let me take his hand in mine. He won’t always be so willing to tell me about his day.

I know from experience that time is not on my side, and that I can’t take these special moments for granted.

RELATED: A Letter To My Kindergarten Graduate

When I was in college, the song Closing Time by the band Semisonic became a huge hit. One line of this song has always stood out to me—“Every new beginning comes from some other beginning’s end.” Each fall marks the beginning of something new. But each spring around this time, I face another ending. I never knew how much joy I would feel watching my children learn and grow. But I also never knew how bittersweet the end of each school year would be.

When you are holding your brand new baby, imagining all that is to come, 18 years can feel like an eternity. And there are certainly stages when the days feel especially long as you trudge through sleep exhaustion, toddler tantrums, and threenager attitudes. But once your kids are in school, time seems to speed up. School years go by in a blink of an eye.

Before you know it, a year has passed and you are saying goodbye to yet another teacher, wishing time would pump the brakes.

When your youngest starts kindergarten, you feel time slipping away even faster. You find yourself holding on a little tighter to the small hand resting in yours. You try to savor every hug, every time they call out “Mommy!” with a huge smile on their face. You try to live in the moment as much as possible. Because you understand what a gift these moments are. You know in the years to come, you will look back on this time with a mixture of happiness and nostalgia for what was.

RELATED: I Blinked and You Went From Kindergarten To College

When I pick up my youngest from school on his last day of kindergarten, I know he will be excited that he is now officially a big first grader. And I will celebrate this new beginning with him. But as we walk down the sidewalk together, my heart will also ache a little as I face yet another ending. And I will be even more grateful for the little warm hand nestled in mine.