The Winter Selection Trials every year is an event wherein they test the candidate's capabilities and make a thorough analysis of their skills in order to give them an opportunity to graduate early from the academy. However, early graduation doesn't necessarily mean that they have finally completed the academy's intended school year.
If the respective student of that school branch were able to win the Winter Selection Trials, his whole section will have the opportunity to graduate early as well. But it is not considered as official as they are only given a choice. Will they stay in the academy to learn more and improve? Or will they join the knights and the exemplary division in order to gain experience on the battlefield?
Those who are given a chance to graduate early because of their victory in the Winter Selection Trials are given a provisional license in order to participate in missions that are within their base of skills including their foundation.