Progesterone is a hormone released by the corpus luteum in the ovary. It plays important roles in the menstrual cycle and in maintaining the early stages of pregnancy. It may also be involved in the growth of certain cancers.
I've been following various people's posts about the GRE for 10 months now. Some people don't study at all for the GRE, some study for a weekend, the average is about 2 to 3 months, and some study for a year or more.
So you might not even know if you need a retake until about 2 weeks after the test. This means that ideally you should actually take the GRE at least 36 days (15 days to get your score + 21 days to schedule a retake) before your app is due.