early late

[atabitaraf]

A teacher for this class should be on page 25 today.
1. He is on page 22, so he says 'Hey students! we are late!' (is it ok? or you say s.th else)
2. He is on page 28, so he says 'Hey students! we are early!' (is it ok? or you say s.th else)
3. He is on page 25, so he says 'Hey students! we are on time (or on page)' (is it ok? or you say s.th else)

[JohnParis]

The "early/late" concept of time is not applicable to your sentences.
It would be more natural to say to your students "we are ahead, we are behind or we are on schedule.