Confused help

My average cycle length is 57 days according to eve . Yes my period is very irregular🤦‍♀️ my last period was 07/28/2018 however this cycle is different it’s kinda shorter eve says my period is due on the 2nd of September , which would make it 35 days which mean I ovulated cd21. Which make me 9dpo . But my old cycles my o day would’ve been different . I wanted to know can I trust this app to be accurate or any help from anyone would help thanks 🙏