Should I take this GRE attempt or reschedule it?

Hi. I’ve registered my GRE on July 15 but I’m not sure if I’m ready to take it yet. I know I need more preparation and I’m quite certain that I will have to take the exam for the second time after this attempt in order to improve my score. Should I just take this GRE and then register for another attempt later or should I spend $50 to register this July 15 exam to another later date? Thanks!