Me and my girlfriend had sex on may 29 of 2015 and according to my count it was day 15; we used a Condom and I did not ejecualt inside of her. Iam worried because it was just a day after she would ovulate; however she told me that she had ovulate on the 27 she uses a tracking app on her phone and showed me she had loged her priod since the begins on the year; her longest was 28 and her shortest was 25 it said her avrage was 27.

Is this information reliable it means we had sex once the egg had died if not and she did not ovulate on the 27 but on the 28 should I be worried?? Once again I did not ejecualt and we used a Condom

Thanks