The Quiet Type

I just got my copy of Quiet: The Power of Introverts in a World That Can't Stop Talking. I love it. I have no idea whether I'd call myself an introvert or an extrovert, but I am really enjoying the book regardless. I had to do some shopping today, shopping for gifts for parties. I don't know if all these upcoming dinners, teas, showers and weddings that I will be at mean that I'm an extrovert. I love to be with people, to meet new people, but I also love deep and reflective time alone. I would never choose to spend time alone if I have the opportunity to be at a party, though, so I don't know where that leaves me; I don't know if it matters. Is it imperative that I label myself as one or the other, and aren't the majority of people a mix of both?