I think being a CNA first can be to your advantage, but I think you can do just fine without it.
However, I do think it is really important to work as a student nurse extern or whatever they're called depending on your hospital/area during school...gives you some valuable on the job experience that's a little more "real world" than clinicals.
The only reason I got through nursing school was b/c of the SNE job I had (and I was a tech first.) I HATED most of my clinicals and nursing school, so it helped keep me sane.
But, if you can't, you can't.
I think rude people are rude people, no matter if they've been CNAs or CEOs before nursing school. As long as you keep in mind to treat people with respect no matter if they're an MD or housekeeping, you'll be fine on that end.