I’ve got a teenager. My firstborn, my only son is 13.

Just as quick as they all said he would, he grew up and out of that little boy stage I used to know.

You really don’t think about this stage—the big-kid-not-quite-yet-a-man stage—when he’s that cranky little baby who won’t sleep (and didn’t sleep a solid night through until he was about two).

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You don’t think about this stage—the quiet, keeps-to-himself-and-wants-his-privacy stage—when he’s flying around the house in his Buzz Lightyear costume all afternoon.

You don’t think about this stage—the voice-awkwardly-changing-an-octave-deeper stage—when you’re busy listening to him sing the Caillou theme song every day before his nap.

You don’t think about this stage—this texting-friends-and-discovering-cute-girls stage—when he’s holding your hand dragging you toward the slide at the park.

You don’t think about this stage—this prefers-to-be-dropped-off-at-the-movies-alone stage—when he’s begging you to play trucks and cars on the floor with him.

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You don’t think about this stage—the eats-everything-in-the-fridge-all-day stage—when he refuses to take his paci out at the table during mealtimes.

You don’t think about this stage—the sweaty, after-soccer-practice-stinky-sock stage—when you’re watching him splash around in a bubble bath after his first day of preschool.

You’ll not think of this stage—the won’t-be-caught-dead-hugging-mom stage—when you’re holding him tightly through his cries during shots at the pediatrician’s office.

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You won’t think of this stage—the only-wants-the-most-expensive-iPhone-for-Christmas stage —when he’s peeking behind doors and corners looking for his mischievous elf every day in December.

You don’t think about this stage—the impossible-algebra/integer-homework stage—when you’re snuggled up next to him in a toddler bed reading Chicka Chicka Boom Boom at night.

You won’t think about this stage until you get here, wondering where the last few stages went. Wondering where the soft baby hair on his head went. Where the wiggly teeth, toy dinosaurs, and his stuffed piggie have all gone.

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It’s going to sneak up on you.

It’s going to tear you up inside a bit.

It’s going to make you cry harder than you did on those sleepless nights 13 years ago.

But you’ll learn to appreciate this stage too.

Because it’s working.

All the things you did at every previous stage. The parks, the giggles, the hugs, the lullabies, the picture books, and snuggles—all the things that have made him HIM.

Everything you did up to now is still alive here in him today at this beautiful, big-kid-not-quite-yet-a-man stage.