Suppose your standard is 12, then you should at least complete the ability of 15, because in the exam, some nonstandard ones can't count me in, and there is your mentality. If you are nervous, you can only play 90% of your state, so you must complete several more abilities.
If your time in a month is less than 15, it will be difficult. If you pass normal training, you have a 60% chance of achieving it, provided that your training will be more bitter.
Many soldiers do it more times by shaking their bodies. If you learn these movements, you can complete eight with your existing strength and endurance, and you can exceed 12 in just a few days. Of course, this kind of training is easy to get hurt, so it's best to find a gym and a coach to guide you.
If you still have plenty of time, for example, two months or more, I suggest the most reliable way to improve your absolute strength, because in military training, you will often use these movements, and you will rely on skills to improve. Even if it reaches the qualified level, it will be very tired later, because the foundation can't keep up.
Normal pull-ups require muscle coordination, latissimus dorsi, biceps brachii, forearm muscles, and abdominal strength. You should deliberately strengthen the strength and endurance of these people. You can choose to go to the gym and exercise every day to ensure adequate nutrition and not gain weight. Otherwise, muscle exercise usually takes 48 hours to basically recover. If you practice every day, you can master the degree and how to practice.