Should I Do Oct/Nov?

Hi, I am an As-level student, my first trial is gonna be this may/june 2025. I have been studying, not as productive as I should tbh since December. I am taking 4 subjects (Math, Biology, Chemistry & physic). I truly aim for atleast 2(A)s. Do you think it’s possible for me to achieve that in 3 months or should I do it in Oct/Nov (which I really don’t want to unless I‘m left with no choice). And If it is possible may someone please tell me what plan to follow? Many are telling me to memorize the book but I don’t think I have time for that. And so far whatever I have studied I’m really seeing no result on my grades with, Tho I am have understood most of the subject. Please help me here & thanks for your time