I saw this and could so relate to it. I'm an introvert. My husband is an introvert. My daughter is an introvert. We're a family of introverts.
People are surprised when I tell them I'm an introvert because I'm not all that shy and I love being around people. But I also love my space and time to myself. As a matter of fact I need time to myself or I start feeling very overwhelmed.
When I read this to my sixteen year old daughter we had to laugh because this is so her. It fits her to a T.
So the next time you think a person is just "unsocialable" or "stuck up" ( I used to get this a lot because I used to be very shy) think again. They may just be an introvert. Or maybe very shy.
Just remember that introverts just need their space and down time.