why would do app asume I would have a 26 day cycle when my cycles are always 28-29 days!?

Stupid app got me excited ! I had in mind that AF was supposed to show up on the 5th . I've been trying to stay off the app a bit more now , but I missed my period on the 5th so I tested and got a BFN. I then realized it was only CD26 but it predicted my period when I always get it CD28 or 29. I said "my period is late" and it moved it to the 8th. Now I have to wait to the 9th to see if AF comes or not . My husband told me he had a dream that I was pregnant and that got me very hopeful ! Hoping this is our month ! I'm a house wife so when my husband give me my Xmas gifts it would be amazing for me to have something to give back to him ! Baby dust to all the ladies still in this month ! 🙏👶✨