[Lucy's POV: ]
There were Class A to Class L in the academy and depending on the performance of all the students in the entrance exams, these classes were assigned after carefully examining many of the factors. However, in the great academy of Idyllia, it didn't mean that one who has received a certain class would remain in that certain class.
'The classes were reassigned every year depending on the next exams and the students' performance through their previous years,'
Someone from Class A could be demoted to any of the other classes while some from the lower classes could climb up to the higher classes depending on their performance throughout the years, and this happened in all three years.
So, if someone has class A in the first year, in the second year, they might also go down to class B or C, and in the last year, they might also come back to class A depending on their performance or go down to even lower classes.