Is an IQ of 104 good for a twenty year old?

That is about average. However, the Intelligence Quotient is only a rough approximation of a person's overall mental abilities, and should not be thought of as a means of measuring one against others. Creativity is not directly proportional to intelligence, and the IQ does not address a person's ability to perceive their own intuition, which is a powerful tool in coping with every day life. People with high IQ's often have difficulty dealing with mundane aspects of life, and many develop some type of mental illness or disability. Being near the center of the range only means that you are less likely to find life depressing, illogical, or mystifying.