Period prediction complications

Justine ♡ • MAMA to a beautiful boy. ♡

How accurate is <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> if you input your period every month? <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> says I’m late but Flo doesn’t