Sucess using glow

Has anyone gotten pregnant using specifically the <a href="https://play.google.com/store/apps/details?id=com.glow.android">Glow app</a> but is irregular month to month? I track everything on this app but in feb. AF came on the 6th lasted till the 11th now Glow said my FW was 21-27. I have looked at other sites and the OPC says I was to O on the 14th of feb.

So as you can see I'm confused.

Ps. Thank you for reading my rambles.