I am sure the tutor would be able to guide you better, but in my experience P4 is a very difficult course (following on from f9) but relatively easier to pass than p5. I passed in 2nd attempt because the marks tend to be more solid than p5
In p5, the course has a strong resemblance to P3 and to F5 ofcourse. Its a much easier course than P4 in my opinion… but somehow it can get very tough to pass. I passed in 8th attempt o.O but very relieved at this point.
If you were good in F9, go for P4. , Otherwise you could consider P5.