Assalamo Alaikom!
Brother! you have three months and six days for preparation. This time shouldn't be very short for an MSc. degree holder. you can do it brother. If you are not doing any job right now then you can study at least 14 or 15 hours per day. By doing this you can cross thousands of aspirants who have started their studies some months ago and they are studying five or six hours per day because of their jobs. So what is the matter?. Start studying right now, you have time.
If you don't qualify, God forbid, then at least for the second attempt you would be confident enough. And you will also be able to get good marks in the coming screening test. I don't see any way of confusing yourself. Motivate yourself rather than confusing. Go ahead avail this chance.
Good luck.

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"Whomever Allah guides, no one can misguide, and whomever Allah misguides, no one can guide." Al-Qura'an.