Do you think it's fair to give more time off to ppl?

Hi, at work we are all taking CFA exams. I asked my manager this week whether I could take 5 days off for the exam. He gave me 3 days but then would not let me take 2 extra days off. This girl working with me in the same department doing the exactly same job at same level got 5 days off. The reason? Cos I told him 1 week late and we just started a project 1 week ago. Which has a deadline of 3 months, apparently he cannot give me time off. Why? COS my extra 2 days off will fail the project which is due in 3 months time? There are other ppl in the same department and they have managed to get up to 2 weeks off. Why? Cos they told their managers 1 week earlier. I can see that I notified late, but I still do not think this is fair? What do you think?