Glow Changing AF days on me

Farnaz • 👶🏻🖤🖤👼👼🖤👼🖤👼🌈?
Hi everyone. I am 38, trying for #1 this is my first cycle. Trying and with glow.
​This morning, glow decided that I am getting my AF on the 7th instead of 1st, which was the projection and what my usual cycles are (about 37 days).
​Anyone has any clue why it would do that? I doubled checked all my entered I do and those have not changed.  
​Thanks