Don't wait until the last date. Every year we see kids do this and then get sick or turn an ankle and then panic. Take it a month or so ahead of the end date and that gives time retake. Practice every few weeks under test like conditions to understand how fatigue will impact things and get rid of the jitters.
When you get your candidate package you can see your submission deadline on the application portal. The date depends on when you receive candidate status so everyone has a different date. The absolute latest date is January 31st but if you gain candidate status in the next few months it will likely be before the end of this year. Hope this helps.
You have a personal deadline that is four months after you open your candidate portal/are accepted as a candidate. The earlier you start, the earlier everything is due. There is no single final date like at USMA and USNA. You have to absolutely pay attention to the date listed in your personal application page. If you start 4 August, your deadline is 4 December.
So, if you are struggling--start training now--and open your portal in late August and give yourself the fall semester. You do not want to wait. Remember, you also need to plan to apply for all of your possible nominating sources, take the SATs/ACTs again in Sept/Oct, and you want time for the DODMERB as well as gathering letters of recommendation, transcript requests and other items. If you are healthy, a good CFA score is within your grasp--start now with the practicing and time your application window to support reaching your goals.
I think you are making a mistake by waiting till the end to complete the CFA. What if you are injured and can't take the CFA until after your dead line? The CFA is used to demonstrate fitness and your ability to succeed physically as a cadet. You do not have to max the individual scores to meet the purpose of the CFA. Strive to do your best but don't wait till the last minute. Its extremely unlikely that having 5 more ft or 10 seconds more will be the deciding factor on your admissions as long as you are clearly demonstrating scores/times that are demonstrating fitness and ability and you are academically strong and have a solid well rounded application. You have been training for a year already? If thats accurate and your training has been targeted to fitness (aerobic capacity, core strength, balance, flexibility, etc) why do you need more time still? Something isn't computing....Best of luck to you!!