Lack of emotional development, can even sabotage or derail academic prowess.
Maturity, also. But it has nothing to do with age.
There are many adults, who are immature and emotionally arrested.
Being late born or the youngest in class, is not a determining factor.
Both my kids are late born. They were fine both emotionally and academically
Emotional development and academic skills, do not coincide nor occur in tandem.
Emotional development, is also impacted by how a child is taught and guided. Same for academics.
Both in school and via parenting.
Being a class clown or not listening, may also be a child's way, of coping. With stuff they are not yet mature enough, to cope with.
It is like an outlet, a child's way of venting etc. or fitting in. Varied reasons.
But they gotta learn, how to behave.
For me, I rather my kids be emotionally able and self-assured and to KNOW themselves, than to be an Einstein.
There are also many academically high level people & kids, and they have no emotion aptitude at all. And they have bad attitudes. And always think they are just a special little snowflake, just because they are "smart."
But they have not grown... or developed.... emotionally at all. And they still, even if academically smart... are ill behaved in class and elsewhere.
I know some kids like that, at the school where I work.
And let me tell you, they are always, causing trouble for others. But they are in the GT classes.
As for Teachers, there will ALWAYS be, a Teacher that is not your cup of tea or your child's. But that is life. And a kid... NEEDS to learn, resilience and adaptation. And how to try their best, despite. That... is key, in life.
Both my kids have had teachers they did not like. And there are a couple of Teachers I did not like, that my kids had. So what. They dealt with it. I dealt with it. They STILL enjoyed their year and I did too. And the Teacher was fine!
Successful people/kids, are not necessarily, the "smartest" in their class.
One of the worst things for a kid to learn is: that just because they are "smart" that they don't have to listen or behave with others. Or that, if they are "bored" they can just act up and use "boredom" as an excuse and their parent will cater to it.