Now 2 days late

Melissa
Ok so this my first time posting on Glow. I was due to start on Sunday and as of right now I have not. Going back to the last few months and tracking my periods, I have never NOT started on the day I should have according to the <a href="https://play.google.com/store/apps/details?id=com.glow.android">Glow app</a>, except for the times I may have stated a day early. But I have never been late. I wanna take a test....but then I don't wanna see a negative test and have to be disappointed. LOL Thoughts? 
Mel C