I am undecided what you find so unbelievable about Roland's schooling process. IIRC They are only instructing basic literacy (maybe standard math? You should not keep in mind), not even at the extent of modern Key school curricula. Only the witches get a more specialised schooling with Scroll training. http://readreleasethatwitchnovel16913.mpeblog.com/16566033/how-much-you-need-to-expect-you-ll-pay-for-a-good-release-that-witch