Period length

Danielle • Mommy to a beautiful little girl and pregnant with #2 via IVF 💜
Why does glow have my period length at 28 days. When my length is 31 days?!? How do I change this! It would
Be nice if glow let you input your cycle length, and then do its predictions from there. Pretty much all other <a href="https://play.google.com/store/apps/details?id=com.glow.android">fertility apps</a> let you select your cycle length!
Kinda frustrating each month knowing my predictions are probably wrong!