He is small, but growing, into a little boy with the colt-like legs and the rough and tumble way of moving from one place to another that occasionally results in a faceplant on the floor.
Still little enough to hold my hand everywhere we go, he hangs on to me at night, telling me stories about his day, or random bits of information he feels a burning need to communicate. "But I have so much to tell you, Mommy!"
He stepped into a new preschool halfway through last year, with just about no hesitation and no negative thought. None of the girls' worry -- will they like me? Will I have friends? Will I be okay all day?
He has never been that self-assured before, ever.
Last week, I put him on the school bus for his first 'big-school' experience -- a summer school-readiness program for rising kindergarteners.
After three children, this I know is true: once they enter school, the years flip by with increasing speed, blurring from one to the next like a time-lapse video. One day, you are snapping a shot of a shiny new kindergartener proudly wearing his backpack and carrying a new lunchbox, and then like magic, you look through the lens of your camera to find a young man in a cap and gown.
He is fascinated by the way things work. He identified the mechanics of a car seatbelt buckle when he was four, and has created large Rube-Goldberg-esque machines in the living room that he pretends can make coffee, or ice cream, or dispense any manner of toys or books or other trinkets.
He is starting to read. He can do some simple math. He questions everything, and wants to know how all the machines work. He is constantly chasing, and failing to catch, his big sisters.
He wants so badly to be big.
But he climbs into my lap when I sit on the couch, or the porch, and he slips into my bed in the dark early-morning and pets my arm or touches my cheek. He wants to be with me wherever we go, or he wants to go nowhere and stay at home all day.
He is my last, my baby, and the little boy I didn't know I wanted so much.