Introversion and shyness are not the same.
"You're so quiet." "Don't be so shy." "You should get out of the house more." If you are an introvert chances are you've heard one or all of these statements at some point. But how often has someone said to you "You seem like you might be an introvert."? Probably never. Often introversion is mistaken as shyness, but the only characteristic shared by these two is that both involve limited social interaction. Aside from introversion being one of the 16 personality types and shyness being a feeling, There is one major difference between being introverted and being shy according to science... it's a choice!
A shy person may want to engage with others, but has a fear of doing so. Whereas introverts are not fearful and can actually socialize rather easily. They just have a strong preference to do it in small groups or not at all in some cases. In other words introverted people may not socialize because they simply choose not to. They may choose to stay home or skip the office happy hour because being around people is draining for an introvert. Yes introvert hangover is real! They are not afraid of social interaction, they just don't like the drain that comes from it. I mean be honest who gets up and says "I feel like being mentally drained today!"
So yes introverts may be quiet. And yes introverts embrace being a home body rather than going out. However chances are an introvert is not shy. Maybe, just maybe they simply don't feel like talking.