Which one

Olivia • •23 •Nila Grace 💕 1/25/19 •wanderer🌻🌲 •work in surgery 👩🏼‍⚕️💉 •will friend any kind soul 📫🤙🏼

I have two apps that tell me two different days I’m ovulating and fertile... up to a week difference which one is accurate? I don’t want to do OPK’s I feel they’re a waste of money