Then, while it is young, accustom your new pet to people young and old, other animals, and a variety of different situations. Early socialization is very important. If you are considering adopting an adult animal that is known to be aggressive, be realistic about what you can expect. Even if the problem was aggravated by the previous environment, rehabilitating an aggressive animal is a big project. To believe the animal needs only tender loving care is a mistake.
Animals do change, but it takes dedicated work and lots of time.
An aggressive pet is a liability, especially if there are young children around. For more information on animal health, contact your local veterinarian.