Wow, we are so alike, you and I.
I've got extreme anxiety and tend to panic a lot. I keep a little bottle of Rescue Remedy in my pocket at work for when I feel a panic coming on.
Anyway, I just got a job at a skilled nursing facility last week, and started on Saturday. I had all of the same worries as you: That people wouldn't like me, I'd be annoying, I'd be too slow, I'd be a bad CNA. I've gotten over the fears of those around me hating me because once you start working, you realize very quick that you're not there to make friends. I know that sounds so cliche, and I would sigh everytime somebody told me that before this job. BUT, it's true. Also, every single person (spare a couple of girls that sneer at me) that I've met has been overly friendly and has tried as hard as possible to make me feel welcome. If I were you, I would ask to be trained on more than one shift, which I did, just so that you can kind of get a feel for the type of people on each one and know which one you would prefer to work on if the oppurtunity arose, you know? I prefer 2nd shift, but my home shift is 1st. Blah.
As far as what you have to do to be a good CNA, wow there are a lot of things here, so I'll just tell you what people dislike. Don't gossip, ever. People will write you off quickly unless they gossip themselves, but don't get in with those people. They're detrimental to your job. Try and be as helpful as possible, even if you're slow. If they see you're making an effort, they'll overlook your slowness at first. Smile and be friendly to everybody, this is the biggest tip. Just be friendly, and be open to constructive criticism.
I'm still struggling to get the tasks of this job down, and it's not a walk in the park. But just remember why you did this in the first place. <3