Like the person above me said, I think you need practice before owning a dog. Or a least lots, lots of research. I think most new dog owners end up giving their pet away because they can't teach them the basics: where to do the necessities, not to chew on furniture, etc. It can be really frustrating, specially when you don't know if you're doing it right.
Thankfully my dog is really educated now (it took a while to teach her), but I understand how tough it can be to teach a dog, specially if you haven't had a family pet and never learned by watching someone take care of them.