Help??

Can someone explain to me with either screen shots of whatever. How to change my app to make the ovulation prediction right?

I'll give you an example. Glow said I wouldnt ovulate till the 17th this month.

When really I ovulated on the 13th, but I had to wait to get my period for it to pick it up. Is there a way to change the ovulation so it's more aaccurate. Like the day I get a positive opk for peak ovulation can I put it in the same way I'd log it on my calendar.