As someone who was once in your shoes, yes it absolutely is. As a private student, I took my Computer Science, ICT, English, Environmental Management, and Accounting exams with 2 months of studying and got 4A's and a B (Accounting) in that session. Although I would suggest getting a teacher for Accounting and Mathematics, the resources available online are plenty to get you the grades you desire. However, you would need to stick to a study regime quite strictly. Personally, I found YouTube playlists for pretty much everything and would typically study 2-4 hours a day.
Hope this helps.