The moment a BF starts bagging on my quietness/shyness/social phobianess (whatever it may be) it would be time to end things. I could accept/overlook many things, but this is something I take seriously. I want a partner who understands this and accepts who I am.
I always have a hard time meeting my BF's friends or family. It takes me a long time to warm to people - if at all. But with more and more exposure, I will become more comfortable. Often, family and friends are quick to dislike me or just think that I dislike them. There was only one BF that made me feel crappy, but he was a loser anyway. After I went to a bonfire with with his friends/family, he was like, "You didn't talk to anybody." And I don't care (as bad as that sounds) I was friendly and smiled - and that should be enough until I get to know these people better. I WILL never be the type who will jump right in and act like we have known each other for years.
Actually, shortly after this incident, he broke up with me. I think his family's perception of me helped form his idea that I am a bad person. He was like "I don't know. Maybe we are just different." And I said, "Do you want to break up?" And he was like, "Yeah, maybe." And I simply AND happily said, "Okay." And not too long after, he tried to get back with me and I would not have it. Again, I won't consider someone who made me feel bad about who I am - when it's actually NOT a bad thing about who I am. I could see if I were dissing people or just plain nasty, but I was friendly the best way I know how to be.
The thing (well two things) that angered me most about your post is that she said to never use the word 'introvert' again. As if it was in the same realms as the 'F' word or the 'C' word or taking God's name in vain, LOL. This is what is wrong with our society. People think being an introvert is a bad, awful, nasty thing. But, I honestly think we need more of them in this world. If I were you, I would try and use the word once a day - at least - to spite her. Maybe even twice in one sentence! Introversion is NOT bad and you should NOT feel shame in your introverted self!
I am also saddened that she did not acknowledge your efforts to get and know her friends. You deserve kudos for being courageous and friendly with them - even though it does not come easily to you.
And last, but not not least, I do have to defend your GF in a way, too. I think many times partners get downright frustrated and angry with us quiet folk because they know us on a deeper level. I think, in a way, they value what great people we are and it frustrates them that they can't show their friends and family that. She probably has been telling them so much about who you are - whether you are funny, sweet, creative, etc., but when they meet you they might not pick up on the same things she sees --simply because it takes time to warm up to people. So, I think this might be part of her frustration as well!