since u have 3 papers exempted it would take 2 years if u are a full time student.
You can take as long as needed for you to understand - as it is theory - if you sharp and can absorb quickly - then read through the book and write an exam - as long as you get 50 - there is no time limit - you can study at home and write an CBE every 2 or 3 months as long as you pass - you can continue onto the next subject