I've been on yasmin for about 4 years. I've had early and late periods while on birth control. I don't think either of you should worry. For about the last 3-4 months, my periods have been either late or early without messing up pills and right before them I didn't feel any pms symptoms at all. I'm healthy, not pregnant, and don't mess up my pills. Sometimes, it just happens. I've been 4 days early and 3-4 days late before. If you go a week without a period, I would start to worry, but not right now. I think you both are fine. Hope this helps a little!
Jess