I remember the first time I walked into my counselor’s office, all bruised heart, frayed edges, and performance anxiety. He wanted to open up by talking about one of my least favorite subjects: me. An initial topic was birth order, which sounded like some kind of hippie nonsense–what would that have to do with anything? I wanted practical advice on how to make my life better, how to get what I was missing. Instead I found myself talking about my chronological location within my family.

It mattered, of course. It still matters. Oldest children tend to share many of the same traits: tendencies toward perfectionism and being tightly wound (WHO ARE YOU CALLING TIGHTLY WOUND??!!!), a drive toward achievement and taking on responsibilities. This is all a nice way of describing Type A control freaks, of which I am chief.

But there’s also the relationship it granted me with my 13-months-younger sister: I don’t carry a growing-up memory that doesn’t have her in or around it. From protectiveness on the school bus to a multi-media rehearsal-dinner toast involving provocative childhood bath time photos, I have always been aware of my (often self-appointed) role of overseer, of protector. During the years between The Kid’s birth and Little Brother’s gestation, I imagined a family unit in which TK would have that same role I did, a younger sibling to help define his place in our family and the world.

Their first meeting, in the hospital, was anticlimactic: TK’s palpable relief upon seeing that his parents had not abandoned him after all was countered by his total disinterest in the tiny baby resting on my lap. Once we brought LB home, though, something shifted. TK would sneak moments with him, often when we weren’t looking, grabbing a socked foot and holding it against his cheek, patting a still-closing skull while I sucked in my breath, handing over toys to an unconscious, swaddled ball of warmth. Contrary to my fears, he seldom showed signs of jealousy, of his spot being usurped in our kingdom; instead, he mostly ignored LB or showed such tenderness that my hormonally-ravaged heart flew out of my chest. He seemed to intuit what he was unable to express himself (an ongoing talent of his): this new occupant of our home was bound by blood, not going anywhere, and had shuttled TK into the position of older brother.

Sometimes, though, hierarchies don’t perform the way they’re designed to. Sometimes positions shuffle, traits deviate, circumstances don’t bend to the expected order. Like when my bitch sister got married five years before I did then stole my thunder by birthing the first grandchild. Just as an example.

Or when we encourage TK to vocalize the sounds we’re working on, urge him to give us a “mama” or “bye bye” and he looks back at us, all “I ain’t no parrot,” then returns to identifying numbers and letters and LB calls out “mama!” from across the room, a pleased grin on his mug, this action so simple and reflective for him, carrying none of the difficulties and hurdles that TK faces. I voiced this to a friend yesterday whose son faces some of the same challenges, how watching LB meet his milestones is bittersweet: the joy of seeing these steps achieved countered by the sorrow over knowing how challenging they still are for TK.

“What do you think it was that finally helped him speak?” I asked my friend, and without hesitation she replied that it was his big sister. And I considered it, how LB is on his way to talk before TK does, and how the little brother may end up being the teacher of the older. I think about how I imagined their relationship: a little bit me and The Sis, a little bit Harry and Wills, back-and-forth banter and hijinks and sniping and affection, and I watch as a story that is like that but also very, very different plays out.

TK arranges his cars into a perfect line and LB tosses his food off of his highchair tray like confetti in a parade, sprays of disorder upsetting the natural order of things. Or maybe revealing the intended plan. I am all about a preconceived idea of what should be, and every day my kids both meet and defy that idea. Every day grace both meets and defies that idea. It answers the mystery that it creates, roles and personalities and meaning taking shape day after day. Like how my younger sister, who is supposed to take my advice, gives the best advice herself. To me.

TK and LB have recently taken a new interest in each other, TK rolling a ball across the floor for LB to fetch and bring back to him. A baby hand patting the head of a preschooler, who dissolves into giggles and signs for more while his younger brother says words. Then they get into a fight. And I can only imagine, though I will underestimate as I always do, how their relationship will grow and change over the years, how they will become themselves both independently and because of each other. How we all do, growing into ourselves and our places both apart from and with each other, shapes blending and fitting and becoming, following a path ordained by a grace that operates outside our hierarchies.