If you are not feeling confident, consider rescheduling PMP exam to a later date

I used to keep reminders on my cellphone calendar as well as on my Microsoft Outlook calendar to a date that was a little more than 31 days, to take a call on whether or not to reschedule the exam. I did reschedule the exam multiple times because
of the following reasons

• Work related aspects in my current job clashed with the exam dates (I had to attend a training on Scaled Agile Framework sponsored by the company that I work for, and the dates of the training overlapped with my PMP exam date)
• I felt I was not prepared enough because I was not able to complete 2 rounds of reading PMP Exam Prep and PMBoK
• I decided to take more practice tests

Note that a fee will be charged if you reschedule your exam within 30 calendar days of the appointment. 

For more information, read through the section on "Exam Policies and Procedures" in PMP Handbook which covers topics on "How to Schedule Your Examination" and "Rescheduling/Cancellation Policy for CBT Exams".