Please help!!!!


So ladies I have a super weird question... and yes I feel like I should know this... but on this app my period starts like clock work. The prediction date is on point every time. I am currently a day late and it’s not common for me. My sister says I could have ovulated late, I am hoping I am pregnant!!! But my question is... if you don’t ovulate the same day every cycle why is my period always the same day like clock work and not this time?