Just to add a different opinion in here, I did not "practice" chewing at all as a pre-op. Once I was post op, I was immediately careful of what, how, when and why I was eating anything. I didn't have to practice chewing slowly; I simply knew I had to!
As for the stages, your body will help tell you when you are ready to move on, though I recommend following your surgeon's instructions. But if you move onto the next stage and have problems, I don't see why you can't back things up to the previous stage for a bit longer before venturing forward again. We all heal differently and every surgeon is different.
As far as your nerves go, I started thinking about having RNY last July and finally had surgery in April. I went through every possible negative thought there was before with the help of my faith, I made my peace with it. Though it seemed like my surgery date would never arrive, I am so glad I had the time I did for my mental state if nothing else. By the day of surgery, I was joking with my nurse and my surgeon, where even three months before that, I was convinced I'd be a sobbing mess the day of surgery!
Take the time you need to find your peace with this, to make sure it is really what you want to do, and to do lots of research on life post-op. Know exactly what you are signing up for and you will be just fine.
