J.,
Do take a class at the hospital that you plan to deliver at, they will give you a lot of information that will help you get ready to breastfeed. I found it helpful for my husband to come with me to the class so that he understood what was normal for a breastfeeding mom and baby.
Also, make sure that your OB knows that you plan to breastfeed, and that it is noted on your forms when you go into deliver your baby. That way they will make sure that you have your baby with you and can make help available to you right away to get things started right. Don't take the free sample of formula at the hospital, it will be too easy to give in and feed a bottle if you are tired, or things are not going quite right. Get a contact for a Lactation Consultant before you leave the hospital, in case you have questions or problems after you go home.
I nursed my first son for 15 months, and am nursing my second right now (he's 7 months). It can be very challenging, and the more information you get before you start, the better prepared you will be. Newborns eat often, I had forgotten how much time it takes the first 6 weeks or so, but it gets easier and easier as the baby grows.
You could also try reading a few books before your baby comes (if you have time). I liked The Womanly Art of Breastfeeding.
Good luck, and know that you are making a great choice for you and your baby by breastfeeding! Not only is it good for the baby, but you will find that you lose weight faster by breastfeeding! And - it reduces the risks for getting breast cancer!
J.
SAHM to 27 month old Charlie and 7 month old Joey