In some ways, it depends what you want to do in psychology. Do you want to be a therapist, or would you prefer to do research? Do you want to become a professor, or go to medical school and become a doctor? All of these areas will have you interacting with people, but in very different ways. Therapists and doctors are taking care of people, whereas researchers are studying and learning about people (and usually welcoming them into the lab to do their studies). These professional interactions are different from simply socializing, but they do require warm interaction with others.
Other traits that are important are being hardworking and persistent, while also being able to admit when you are wrong. These traits will benefit you in almost any career. And, of course, you will be better in your career if you love what you are doing.
I would agree with Jennifer's response. You can do a lot of things when you are a psychologist. There are many different types of psychologists, but most people think of a therapist.
Before you can become a therapist, you will undergo considerable training to prepare you. The training will help you develop skills that are necessary for the job. Personality is less important than your ability to learn those things that will help you do your job. As any healthcare provider, being a therapist tends to attract people who want to help others and who have considerable empathy.
Hope this helps.