Cycle on Glow

Alexa • My husband and I have been married since May 2014. We are the proud parents of Levi Peyton born July 5, 2016! We are waiting for our baby girl’s, Ivy Alexandria, arrival April 30!
I have entered that my cycle is usually 28 days yet my glow states I should start my period today which would be day 20? Anyone have any idea what's going on?