He got into Stanford, he chose to go to FSU, he had exemplary marks in High School. Just because he talks in slang and has a strong Alabama accent, and isn't an Uncle Tom raised by white folks, doesn't mean you should racially profile him as being "dumb".
He misspoke, if this happened during the season, no one would be talking about it, but since it's the off seasons this is a big deal. And sure, everyone should be strong, like I said before, he gave an hour long speech to the kids and messed up his wording in one paragraph of the aforementioned speech.
It's people like you that want him to fail, that want to see him falter because he's an African American that is highly intelligent and is excelling at a predominately white position in the NFL.
Here's the article about him saying he wishes he would have gone to Stanford after the fact.
http://www.mercurynews.com/2016/10/19/jameis-winston-wishes-he-accepted-stanford-over-florida-state/
Call him "dumb", all you want, it just makes you look like an uniformed bigot.