Q.Last spring I had to decide whether my son, who turns 5 at the end of September, should go to kindergarten or to preschool in the fall. I didn’t know which one to choose. Because I knew that this was one of the most important education decisions I could ever make, I asked some friends, some mothers’ groups and some teachers for their opinions, but they didn’t know, either.

I could only close my eyes and make my choice — uncertain as it was — but the decision left me with a heavy weight in my heart. All I know is that I want to do what is best for my son, not just now but for his entire time in school.

Which choice would you have made? What is the prevailing theory? And how much will it hurt my little boy if I’ve made the wrong decision?

A. You don’t have much to worry about.

(Hadley Hooper for The Washington Post)

Parents make a zillion wrong decisions, but your son is much more understanding and resilient than you think, and he loves you much more than you know. For all of these reasons, he will forgive almost any mistake you make, just as quickly as you forgive his stumbles.

The prevailing theory doesn’t matter much, either. Theories on education — like theories on everything else — shift almost as much as the wind, and so do parental opinions. Some parents put their children into kindergarten as soon as they can because they think that their children are smarter than all of the other children — and probably the teacher, too.

Other parents hold their children back for a year — or redshirt them, as it’s called — because they think that older children will shine more brightly than their classmates. And they will, but the younger ones will soon catch up with them, just as late-talking, late-walking children caught up with the early achievers a few years ago. No one remembers who learned those skills first, and no one will remember which children were the first to read and write, either. It is your child’s maturity that matters, not his smarts or his size or how well he knows his letters and the sounds that they make.

To find out if your son is too old for pre-K or too young for kindergarten, you need to watch him on the school playground and in the classroom, so you can see if he looks happy and comfortable to be where he is and behaves like the other children in his class most of the time. And then ask yourself:

Does my son look forward to school and to learning? Does he work and play easily with the other children? If he does, you’ve probably chosen the right class for him.

If not, ask yourself if he looks bored by the information and by his classmates, too, and if he does his schoolwork quickly and then waits and waits for the others to finish. If so, he’s probably too old for that class.

If that’s not the problem, ask yourself if your son cries more easily than his classmates; grabs the blocks or the books when other children are playing with them; drifts away from the circle during the morning meeting; and interrupts the teacher with questions that have nothing to do with the story that she’s reading to the class.

If your son does these things in kindergarten, he probably should be moved to pre-K because an overplaced child will eventually feel bad about himself and then his self-esteem will plummet. That could make it hard for him to enjoy life and to learn as much as he should.

There are other ramifications.

If your son, though overplaced, can get through the early grades, he may still have to repeat the fourth or the sixth grades when the work demands more than a younger brain can handle. This often happens with children who have late birthdays, especially boys, because most of them mature about six months later than girls.

Fortunately, school is not a prison. A child doesn’t have to stay in the wrong grade until he graduates from high school or even until the end of the semester. If the teacher agrees that your child is either too young or too old for his class, you should ask her to move him now. He may be embarrassed by the transfer, no matter how deftly it’s handled, but he’ll be so much happier in his new digs that it will hardly bother him in a few weeks.

Send questions about parenting to advice@margueritekelly.com.