Birth Control Questions?

I was instructed to wait until the first day of a new cycle (after your period ends). It just makes sense that way because you will take the amount of pills in the pack for three weeks and then you will have a period just like normal. If you don't do it like that, it might just mess up your cycle for a month and you could have a higher chance for spotting during the time you would usually have your period but are still taking the pills. It should straighten itself out though. If you are stacking pills though, it wouldn't matter when you start taking them. It will still be just as affective at preventing pregnancy but it could screw up your cycle for a bit.