Good on you for being prepared early. I definitely recommend joining the ABA and doing one of their breastfeeding education classes. Having the information beforehand makes a huge difference and the support is even more helpful.

Nipple rings in the past usually don't usually cause a problem. I have heard of 2 or 3 cases where there had been an issue but this is very rare so I wouldn't give it another thought. Large breasts can make things a bit more difficult at first but with all your knowledge from your ABA class and book you will be fine. Confidence that you can do makes it a lot easier.