When your baby arrives, you'll find that your mothers instinct has kicked in. It won't take long to get the jist of it.(:
I am also pregnant wig my first and plan on breast feeding I had worried that I would do it wrong but I realized that women have been breast feeding for as long as they have been having babies I'm pretty sure there's an instinct in our DNA somewhere. Also, babies are born with a latching reflex so yea just stay positive and I'm sure you'll be an awesome mom :-)
I had my first baby at 18 and I had no clue what I was doing, but I managed to breast feed for a year and a half, it will come, dont worry. It was surprisingly easy and painless for me. There is a ton of literature about different techniques online, and also le leche is a great resource as well. The hospital will have lactation consultants, and so does WIC.
If you want to do it, you can. I went into the delivery knowing that I was totally set on breastfeeding the baby and despite the advise of the nurse that I had (she tried to get me to give her a bottle) I stuck with my plan. You can do it!