No missable achievements (plus 8 unknown)
Sign in with Steam or Xbox to track your progress, and:
Impress Miya on her first day of class.
Accept responsibility for watching over Miya.
Discover Miya's true reason for missing class.
Attempt to get Miya to attend class by force.
Successfully conduct the Tea Party.
Find Miya skipping class outside campus.
Retain perfect attendance via "extenuating circumstances."
Complete the story.