Pregnancy test

Rachel
I had The <a href="https://play.google.com/store/apps/details?id=com.glow.android">Glow app</a>. and then deleted before reinstalling. Before I deleted it the app. had me at a 27 day cycle, but after reinstalling it has me at 28 days. Should I test for pregnancy on day 28 or wait the extra day on day 29?