WarChild has given you very good advice. If you do get a puppy make sure you buy a book called
Before and After Getting Your Puppy by Dr. Ian Dunbar. Dunbar is the godfather of dog training.
Also, if you've never had a dog before... I do not recommend a Rottweiller. This is not the right dog for a first time dog owner. Lots of Rottweillers end up in shelters because their owners never learned how to train them.