The Academy Phase lasts about a year in-game, or ~12 months/missions. After that, the time skip happens, and we enter the War Phase. The previewer from earlier today may have implied that the time skip took them 10 hours to reach (while rushing), in a ~45 hour experience (one route, while rushing).
Oh fuck
Edit: I'm having a Kid Icarus: Uprising-esque moment of "Holy shit this game is way bigger than I thought it was."