Depends on 2e or 3e.Question. Not everyone has the potential to become a sorcerer, right?
2e's stance is that everyone can learn it if they have enlightened essence, though most people can't get anything done WITH it(what with even terrestrial spells often being bigger than their mote pool), and even fewer are willing to take the Trials.
3e's stance is that sorcery is more of a case by case thing, no standard training or education for it, but MOSTLY being rare in some way to succeed at one of the sorcerous initiations, so overall, pretty rare. However, a mortal can get as much out of it as an exalt at the terrestrial level, its just that they don't have the dice to do it safely and reliably.