Help!

So last week I got a pos opk test. According to the 2 apps I use I was suppose to start AF on the 3rd. When I put the pos opk in both apps this app changed af to next week while the other one still says 3rd. I'm not sure which app to follow at this point. They both have been really close with determining af so it's making me very confused. Any help would be greatly appreciated, last month we were just going with the flow only took 5 opks the whole month, no temping and didn't check my cm