Clear Blue Advanced Ovulation Test

I have PCOS and have never used ovulation tests. My cycles are 35 days usually. With bleeding for 5. All the apps based on tracking my period will say I ovulate around cycle day 22. However a friend suggested trying the clear blue advanced digital ovulation test. I took it on CD 14 and saw a flashing smiley (high fertility) and the next morning it was PEAK! Could it be accurate that on CD15 I’m PEAK? And the app is off by a week? I’ve been BD every day since CD10 (today is CD17). Since CD 14 I’ve been having lower belly cramping randomly. We’ve been trying for almost a year . I want this so bad but don’t want false hopes because of a digital test.