I am brilliant, but ecclectic. And I have forgotten a LOT in the last 40 years.
[sniggering with tongue extended in your direction]
Besides, 12th grade standards are pretty low now.
Seriously, my daughter IS brilliant, but an abysmal speller. She recognizes that and, though improving, makes liberal use of spell checkers.
Sorry, it was impossible to resist in that situation. But you're right that 12th grade standards don't mean much; even in college many people don't really know how to write.