I always promised myself that I wouldn’t be one of those moms who mourned the passing of a childhood phase.

I didn’t cry when my kids had their first birthday. Instead I relished the sleep that followed the newborn phase and gobbled up every wobbly first step.

I didn’t weep on my little boys’ first days of preschool. In fact, I embraced their opportunity to reach out into the world right alongside them.

I don’t complain about each inch added to their stature, even though they are quickly catching up to my petite (aka shorty-pants) frame. Actually I watch in wonder as they’ve transformed from babies into boys and now–as my biggest is entering the double-digits–into impressive young lads.

But now, all of a sudden, I’ve hit a milestone that feels more like a road block. And I’m tripping all over myself.

What the WHAT?

My last kiddo is heading off to kindergarten soon … and suddenly I’m a big old cry baby.

Given my resilience–and even pride!–in the face of earlier transitions, I don’t even know how to process this emotion.

I’m at a total loss.

Maybe that’s what it is …

A loss.

Suddenly I feel empty. Which seems so foolish. I look around and my life is so full. And it’s not like I’m losing my sons! They are right beside me–sleeping in their beds, going to church, playing outside, going to school–just “real” school instead of preschool.

Why is it suddenly so different?

Maybe it really has nothing to do with my children.

Maybe it’s me.

It’s my heart that’s changing. It’s my heart that’s empty. I look around and I’m not sure how to define myself. My life has been so full of people all day, every day asking me for things and yelling and cuddling and hugging. And now I have these long stretches of … nothing. Just me.

It’s so weird.

I haven’t been alone in a long time. Who am I when I’m all by myself? I’m not sure I even remember anymore.

I guess that’s really what it comes down to. I’m so used to defining myself in relation to others: I’m the mom. I’m the wife. I’m the _____. (fill in the blank with whatever job I happen to have at the moment) What am I when I have none of those things?

Truthfully, it’s totally magnified right now, during the kids’ 6-week summer visitation, while my boys are with their dad across the country. But I know it’s just a preview for the long school days ahead. Starting in the fall, for 8 hours a day, it will be just … me. And somehow I feel like the ground has fallen out from under my feet.

And I’m realizing …

It doesn’t matter whether I get a job, or find a hobby, or scramble around doing chores and errands and paying bills. In the end those things really can’t define me.

If I really think about it, they never did.

At my core, I’m a Mom. It’s all I ever wanted to be. THAT is my work. That is why I feel displaced. Now I just have to step up and learn how to be a mom of school-age kids.

I was talking to a friend the other day who expressed a similar sentiment. She said something like, “I have this nonprofit, and I do all this STUFF. And it’s important, and I feel called to do it. But there’s only one thing I’m really meant to do–it’s a calling I’ve had for thousands of years, even before I came to earth. And that’s being a mom!” That hit me hard. To the core. It’s her Truth, and I realized it’s mine too.

But that’s my Truth. Others may have a different Truth. And that’s okay! We are each unique and extraordinary in our own ways.

It sounds simple enough, doesn’t it? Defining ourselves. Knowing who we really are–at the core, and then acting on it.

But it is NOT simple. There is no easy answer.

I don’t know how to tackle this next phase in my life. I only know I’m leaving the familiar territory of ‘preschool mom.’ I’m leaving it behind, and I’ll never go back. There’s a certain finality about that.

Right now, in my empty house, with my children far away … I’m hovering here anticipating the coming school year, on the brink of the unknown.

As always, life marches on. And I’ll find my rhythm. Just not right now. At this moment, I’m out of time. I want to remember this space, on the brink. On the crest of the wave.

Maybe someday I’ll look back and laugh or shake my head because “I was so young.”

But right now I’m just here.

Alone.