I just read the whole story up to this point. (Unlike Cobra, I kept reading because I enjoyed it!) It's not the first 'Harry learns about his magic early' fic I've read, but it's very well done.
I'm not too shocked that Harry decided to pass on Hogwarts. I didn't like how quickly he capitulated to DD. It makes sense, but it could use a bit more explanation. In my mind the explanation is that Harry knows (now, if he didn't know before) that DD can fuck with people's minds, so he's not likely to have much traction in the 'regular' world. And by now, he knows about the wizarding government, such as it is, and there's no way he can win there against DD.
You have already shown Harry capable of successful blackmail. I think you'll need a reason for Harry not to be a total asshole at Hogwarts (a la several other reviews). That is, if you don't want him to be a total asshole.
One could be that he knows he's stuck there, and has enjoyed having friends at Xavier. The point system has a way of subverting peer pressure. Another could be a carrot from DD--"I can, of course, make it very easy for you to go back into the Muggle education system at an appropriate level when you are done with your wizarding education." Of course he means when he's done with Harry....
Anyhow. Very well done. Good fun. Looking forward to the next.
Peace-
-Rijl
Author's response
You're actually right about why he capitulated so quickly and no he won't be a total ass in Hogwarts, and yes he will have a very good reason for it.