So as of today, considering it's after midnight, I'm now 13 weeks. I have a few other pregnancy apps…

So as of today, considering it's after midnight, I'm now 13 weeks. I have a few other pregnancy apps and they're all spot on when it comes to how many weeks and days along I am, but it looks like this one has me a week behind what I really am. I'm not sure what or how that happened, can somebody please tell me how to fix it or let me know if maybe I done something wrong? I can't seem to figure it out myself. knowing my luck it's a simple fix and once I find out I'll feel stupid about not figuring it out on my own lol