Ok, I don't have kids, but I'm gong to mention what my sister got told by a friend about having my nephew.

She was like you, saying she was worried if she'll be good enough, etc, etc, and the friend said, "You'll be a good a parent because you do worry and you do care about your actions".

I totally agree, in just caring, and worrying, you're already showing how great a parent you'll be and are willing to be. Good luck, hon. :)