I feel like it would be really helpful if glow recognized your period was late. For instance, instead of it just assuming your period started on the day they predicted, on period day one, it should ask "did your period start" and if you say no, it should ask "are you late". Instead, if you change the period dates manually, it just assumes your cycle is longer which is not the case for people like me who had a chemical pregnancy that made my period a week late. That longer cycle gets averaged in with other months and it could screw up future period predictions. I'm not sure if what I am saying makes any sense or if the app does do this and I just missed that feature. Let me know!