That's an awfully long trip for the first time out! Is this a trail or will you be (horrors!) road-walking? I suggest you practice hard between now and the time you plan to start, both learning skills and physical conditioning. You should take a number of shorter backpack trips beforehand, starting in your back yard and/or car-camping to get used to your equipment and to learn how to handle inclement weather where you can easily bail out. Once you've practiced a while, go on a couple of short overnight trips where you're only a mile or two from the car (again so you can bail out if everything goes wrong).

There is a section on this forum specifically for Backcountry Beginners. There are also lots of excellent articles on the home page of this site. I suggest you read them carefully and then come back (in the Beginners section) with questions.