If you stand up to such an important test, your training is likely to trigger panic. Your mind will not allow you to focus properly when you panic and you may be studying the same material without really mastering what you are learning. If you are looking for online classes of ASVAB, then you can consider preparing for a military aptitude test via https://www.andysasvabclass.com/.
And even if you still find that you studied well enough to "get" the information, you're less likely to remember it in the long run and less likely to apply it over time you can. This is because last-minute learning stores information in your short term memory.
And while this can be helpful for a topic or concept, plugging a lot of information into your short-term memory only creates chaos and confusion when trying to get information on exam day.
Don't sign anything until you pass the exam with the results you need to get the job you want. If they say you have to sign before giving you the test, that's a lie. So go to another office to take a test or go to another city and try to recruit there.
If more than one branch has a place for your career choice, choose the one that has a better loyalty program or gives you more money for college. Most of the people who joined the army became more confident and capable.
They show you how to be successful, and with the experience and knowledge you gain from your chosen profession, you can bring your experiences with you when you enter civil or contract work after you retire, or when you end your day.