I can feel the lynch mob forming as I type, however... I wouldn't worry about RAW just yet. Yes, I always shoot RAW, yes, I'm a huge proponent of RAW, and yes, I think it's better than .jpg, BUT... I also think at this stage there are going to be very few images that you are going to want to keep, and even fewer that you're going to want to keep in six months. At this stage, shooting in .jpg will let you see the images on the computer immediately (to view and work with RAW files, you may need special software such as Adobe Lightroom or Bridge - search "RAW file converter" and you will get a huge list), and chances are you're not terribly interested in learning editing just yet. If you are however, ignore everything I've just said.
That said, if you do start shooting .jpg, I would strongly urge you to switch to RAW once you're reasonably comfortable with the camera and have gained a basic understanding.
Just to play the devils advocate, I know Canon includes Raw capable software with the cameras, I would assume Nikon would also? There's also lots of free software. You can also download a Codec for Canon or Nikon Raw files in Windows 7 so that you can view them using the OS's built in image viewer. I can confirm that Mac OS works out of the box with Canon Raw files (opens them up like any other image) so I would assume it would work with Nikon as well. So, with just a couple minutes of work to download and install the Codec (on Windows, nothing needs to be done in Mac OS), you could easily view Raw images just as easily as Jpeg.
When I first started out, of course, my pictures sucked. They still do, but they sucked more then. I got the advice from a relative to ALWAYS shoot Raw (My camera has never been set to JPEG! I'm so used to working with Raw files now...) But every once in a blue moon, by sheer luck, I'd get a sharp, neatly framed image that I really liked. OR, I'd capture a candid snapshot moment of a family member that, though it has no technical photographic value, is an important memory for me or someone else and I want to keep. Shooting in Raw allowed me, in those cases, to correct the exposure (That was probably a stop or two off), correct the white balance (that was probably left on the wrong setting) and even reduce some noise or use fill light and other features in my Raw processing software to kind of even out the harshness of the on camera flash. Raw does a pretty good job of allowing you to polish a turd! It won't make a masterpiece out of a snapshot, but it can turn an important snapshot from a useless image you are stuck with, that is blown out or dark, into an image that is at the very least, recognizable and something you can share with family and friends.
At least that's me! I'm kind of a 'paparazzi' around my family and I love to have pictures of everything. Without the skills others have to nail the shots every time, I rely on Raw to save important pictures that I failed to produce correctly. You can call it a crutch that way, but in many senses I really consider it insurance. You can always batch-convert to JPEG and delete the Raw files if space is really a concern.
Also, I've almost always shot in manual. I seriously recommend that advice there. I might set it on Auto or Program mode for family events and snapshots, because I didn't want to miss something, but forcing myself to learn how the camera works by setting the camera to Auto is such a huge help. To the OP, go to a cool spot, like a park or a hiking trail, or maybe a busy city street... something with lots of pictures to take. Set your camera to Manual and never take it off. Do some research, learn what the relationship between shutter, aperture and ISO is, and learn what advantages different apertures and shutter speeds have.
For example, when I shoot people, I like to use f/8-f/11 with most lenses. When I was a newbie, (rather, newbie-er) I shot it wide open (lowest number). Why? I thought, more light, more better! But what I found was, using a little more off camera flash, and a little bit slower shutter speed, allowed me to take advantage of the lenses 'sweet spot', that aperture value (f/8-f/11 in my case for my favorite lenses) where the lens is the absolute sharpest. This is just one anecdotal example, but my point is, continue to learn more and more about HOW each of these settings work, and what consequences or benefits each setting can offer. A proficient manual shooter can take some great images!