How Do You Know You’re Ready to Take the Exam?

I keep postponing my PMP exam because I don't feel ready. I'm tensed because my practice exams scores are very low. Today I'm thinking of getting PMP exam help to improve my weak spots, but I'm not sure if I'm overthinking it or it will work? How did you know it was time to just go for it if you had previously passed? What made you think you were ready?