Is there a specific amount if time it takes for any student to graduate?

I guess it depends how many lecturers there are. I think the literacy edict speeds up their learning.

Depends on # of teachers, skill of teachers, literacy edict, avatar bonuses (i.e. leftist author or scholarly), and so forth.

Needless to say, it can vary greatly.

Also the intelligence of the students and whether the Avatar is currently visiting the building.