My job

I open the doors of the teaching building in the morning everyday every morning.  I sleep in the entrance guard room in the entrance of the dormitory.  I blow the whistle at thirty past six (or: six-thirty) (six-thirty sounds more natural to me).  Students run at seven o'clock, eat breakfast at thirty past seven (more natural: seven-thirty).  They read books aloud.  Classes are beginning begin at eight. I will be ready for my class. We eat lunch at twelve.

Comments: How do you get ready for your class?  Is this at a university or a high school?