This sounds an awful lot like my D (now age 17). For us, there was no "fix" for it... just lots and lots of organizational scaffolding and support through the years. Me doing daily checks of her folders for class, online checks of the status of her grades, and reminding her of things. We tried about every kind of organization system there is, but almost every one fell apart. The past couple of years she has had some success with iCal on her computer. As a senior in high school, she is finally showing SOME progress on her own, but she will probably always the "absentminded professor" type. Or as we call her, "the Pigpen of paper" -- Charlie Brown reference for those too young to have followed it.
We were never able to seriously consider a grade acceleration for her because of these issues. But we supplemented a lot with summer programs (Davidson THINK among others). She has done well in high school in honors and some AP classes with some support, and we also got her extra time on standardized tests. Planning now for her launch to college next year.
