BestFriend by William Van Winkle

But with tutors and other tools wired into her brain, Nyshell and those like her have a shot at being normal.
Of course, sometimes parents don't see what their kids do. Things can happen that shouldn't. And when all a girl wants is to have one friend, even if that friend exists only inside her head, that desire may change the lives of millions...if it doesn't destroy her first.
(Previously published under the pen name Bodhi St. John.)