I work 16.25 hours a week but I am on 20 hours a week to include overtime. I start work at 10 and finish at 3pm. Last 2 weeks my Boss has told me my new start time is 930 which is fine. I have 2 kids and need to leave at 3pm to pick them up but my Boss said I can't leave until 315pm. That would make me late going to both schools. I told her this and she said she doesn't care as work has to be finished. A new girl has started last Monday and she is allowed to leave at 3pm and she has no kids to pick up. What should I say to the Boss on Monday?