How does shyness different from social anxiety disorder?

Shyness is a fear of meeting new people. Social Anxiety Disorder is a fear of being around people, feeling as if everyone is looking at you, talking about you, and judging you. --I have social anxiety, and what I feel is basically the "fear of being around people". I just get anxious, and want to avoid social interation. I don't really enjoy being with people, other than my close family, and I have a social "barrier". If I have to mingle with a family at our house, after a while I feel exhausted, like I need some time by myself. NOTE; I'm a teen, and age/experience may have an effect.