That's why I posted about DD, in fact. She was capable of a "perfect" score on under ideal conditions, probably.

She did do VERY well on the SAT-- just not perfect, and not as well as she did on practice exams.

But that could have happened to her regardless of age, honestly. The point is that at 13 she was in that elite category of "potential perfect scorers." Which means that she's in the 99th percentile when compared with 16-19yo's.

Not all of them WILL do it on any given day, either.

Too many other factors, like being tired, nervous, ill, anxious over something else, etc.

Schrödinger's cat walks into a bar. And doesn't.