How accurate is the data on this app?

Nadia

The app says I’m in my fertile cycle and ovulation in 3 days but my OPK tests are very very low. I have a normal monthly period cycle too typically 26-28 days. I’m currently on cycle day 11. First time I’m using ovulation tests too. So I’m not sure what to believe the app or tests. Could my fertile window be further than what the app says? Has that happened to anyone here? Any feedback is appreciated.