I have six dogs actually. An Australian Shepherd, an English Shepherd Australian Shepherd mix, a German Shepherd mix and three other mixes. German Shepherds can be great dogs I have heard they are very loyal but being a bigger dog you should make sure you are able to train him or her well. Here is the AKC's profile for German Shepherds. And here is a little more on temperament.
They will also need some exercise too. Basically you should be prepared to train and at least walk your dog each day. It's always best to start as young as possible if you are getting a puppy, although adult dogs can be very nice and may already be housebroken (which might be easier for you and your parents).
Also keep in mind if you live in an apartment or other small home, it may be difficult to fit a large size breed in. That doesn't mean you can't - but you will have to take extra special care to properly train your pet and get him or her lots of play time and exercise outside.
You may have heard this already, but you should be prepared to put in a lot of time and energy when getting a dog of any age or breed. Puppies are cute to play with, but there is a lot of clean up involved and time investment. Trust me when I say this: if you put in the time you will get a great, loving companion who will always be there for you. Some people find that the effort required is too much - especially if they don't do their homework before adopting a dog. As long as you are prepared and go in and 110% committed to your dog, you will enjoy all the benefits of being a dog owner.
Have you considered a mixed breed dog? German Shepherd mixes are VERY common where I live and your initial costs will be far less. You should expect to spend a few hundred minimum on a purebred (from my experience anyway) and some breeders want even more. Unless you know someone who is a breeder and is willing to give you a deal on one, the initial adoption will likely be expensive.
Mixes on the other hand cost far less and are sometimes available for free. They are also less likely to experience some of the health problems that are common with some purebred dogs. For example, I believe Hip Dysplasia
is a common problem with G.S. dogs, especially if you get a pup from a less-than-reputable breeder. I'm sure there are others, so try searching Google for something like "common health problems in German Shepherds" or something like that.
There is a wealth of information available online, so a few quick searches will likely answer most of your basic questions. Did you have any other specific concerns or questions you were curious about? I'm not a German Shepherd expert but maybe I can help you find the answers either through my own experience or a little online searching.