I am coming up to my qualifying cross country at about 48 or so hours, and I have flown the C150, C172, PA28-140 & PA28-180. All as P1 at some stage. Yes it can be demanding remembering the different speeds and when I went back into the 172 after about 8 hours in the PA28 it did take a few minutes to re-adjust, if in doubt take an instructor along!
The number of hours you have is not important, you attitude and respecting your craft is!