It sounds normal to me. It's not really that common for anyone to actually start the withdrawal bleed/"period" the first day they take the inactive pills. When I was on oral birth control, it took about three days of the inactive pills before I would bleed. If it's your first month on the birth control, you don't know yet how your body will react to it. If you're worried about your period starting during the school day, stick a pad or liner in your undies just in case!

It can take a few days after taking the last pill for your period to start! xXx