It happens every Friday between 9 and 10 AM. And if I sigh a little, I try to remember where I came from. Another time.

In this class at a Children’s Fitness Center, my grandson is one of about 15 kids. They’re three years old, so it’s dicey even on a good day.

My takeaway is simple: How much childhood has changed since 1950 when my mother said to my father, “The rabbit died.” (Anyone who doesn’t get that reference should probably stop reading now.)

When I was a kid, my mother slapped cream cheese and jelly on white bread and called it lunch. The very term “children’s fitness center” would have made no sense. Trophies were reserved for our fathers’ bowling leagues. We sat underneath our desks with legs crossed (yes, we called it “Indian style” to further date myself) bent forward with our hands behind our necks, looking like little pretzels but somehow ready for an atomic bomb attack. Not a whole lot of negotiation with the adult world went on. In fact, none.

So, really, I understand my place in history.

Because these thoughts make me feel 100 years old, I try to concentrate on the class and how much fun my grandson is having. But I’m so often distracted by how much control kids wield these days . . . just by being kids.

Two instructors keep this hour-long session moving with lots of smiles and boundless energy. When they can, they guide the caregivers (moms, dads, nannies, and grandparents, like me) in the direction they want it all to go. When this becomes a fruitless endeavor, they keep smiling, which is a mystery to me.

Most of the class is open ended, with kids free to run and climb on whatever appeals to them. Twice ─ at the opening and closing of class ─ children and adults are asked to sit in a circle and listen and follow in a directed activity. And here’s where it all starts to break down.

When the teacher says, “Okay, everyone move to the circle for Circle Time,” one parent hears this instead: “Not your child, of course. She should keep jumping on the trampoline and filling the room with her lusty version of the theme from Dora.”

Two other children simply refuse to stop what they’re doing, citing ─ in their sweet childhood equivalent ─ that it's just not convenient right now. I resist my urge to act like an old sheep dog and nudge them (and their parents) back to the circle where I think they belong.

Really, I’m on your side, parents, and I spend most of this class rooting for you. I was in the trenches once, too. My firstborn at this age was a force to be reckoned with. At my first preschool parent conference, his teacher used the word intense so often to describe my son that I’m sure that record still stands.

I get it. Your child is feisty. Bold. Advanced. Challenging. But someday she will walk out your front door to coexist in the world that doesn’t love her. Someday she’ll have to face the truth that she is not the center of the universe. Maybe you could start that lesson here so she won’t be so shocked when the real world comes calling.

Here’s where I’m always tempted to say, “I can help you. I have some ideas about parenting that might save you some trouble down the line.” I don’t do that, of course, but it doesn’t stop me from practicing, just in case.

So, to the mom who watches her child cut the line at the balance beam and then turns to me and says with a collegial wink, “Ugh! It’s just so hard for kids to understand how to take turns!” I say: Precisely. Which is why they usually travel with an adult.

To the dad in the red sweater: I know you think it’s okay that your son keeps climbing back up the slide while other kids wait at the top for their turns. It’s not. And you may think he’s showing leadership skills (yes, you have told me he is a leader). He’s not. There is no way Nelson Mandela, Eleanor Roosevelt, or Bono got started like this. I can personally guarantee this.

Class is almost over, and it’s circle time again. I’m next to Mother of the Girl in Frilly Tights. Her daughter is standing in front of all the other toddlers who are trying to watch the puppet show. The children seated behind her are squirming and craning to see what’s going on.

I know the teacher will give it a few beats, hoping the mother will step in. I can almost feel the instructor silently counting to 10, still smiling, hoping. Then the teacher gently assists the little girl’s butt onto the carpet.

Maybe next Friday.