Wonder weeks app

For those who use it, did you guys enter your LOs due date like the app says or the birthday?

I’ve had the due date set up and I didn’t notice anything when the app said my LO should be going through a leap (with the two previous leaps). I changed it to birthday a few days ago and a day before she was suppose to have a leap she started to be very fussy and crying a lot throughout the day (3 days now) while according to the due date she shouldn’t have her leap for like another week 🤷‍♀️