[Latte]

The chances of her being pregnant are miniscule, as explained. It could also be that her period isn't as regular as she thinks it is and is only aware that this cycle is longer than normal because of this concern about thinking you touched her with your cum. Stress or ill ness could also cause it. Heck, my period just totally skipped a cycle one time when I moved out of my parents to a whole other city. Starting on birth control can also cause you to miss a period.

If she doesn't get her period within 14 days of the expected date, she can either wait to see if her period will come the next cycle or she can investigate relevant other options, such as following up with her doctor/nurse/public health person if on birth control. If she misses 2 periods she should think about related health issues just in case.