Answer:
When they go to bed and what makes them stay up late
Explanation:
She would most likely need to know what time they go to bed because that could be a large factor in when they sleep. If they go to bed at 9 pm, then they wouldn't really benefit from a later sleep because they only get a few hours of sleep even if school started later. Meanwhile students who go to bed later would certainly benefit from the earlier start time.
Also she would need to know why they go to sleep late. For example, homework makes them stay up late because they need to finish their assignments, work on projects, study, etc. Another example is after school activities, students could arrive home late due to sports and have to eat dinner right as they come back, forcing them to do work late at night.
