I think in general it's always good to get as much experience as you can. As for nursing school admission, it depends on the school. Here in Oregon, entrance is granted based on a point system out of 70 points. You can get up to 5 or 6 points if you have worked a certain amount of hours as a CNA. You might want to check with the schools you are planning on applying to and see how they work. Best of luck!