Brave-girl,
Yeah, you!
You want to change something thats constantly changing? - Personality
Your biggest problem is that you are holding onto an image or idea of who you think you are (shy-girl), an image of yourself which you believe to be true, when in fact its not true at all, its constantly changing.
Find a photo of yourself, this is you in that moment, that photo seems to show you as being fixed in time. You have changed since then, if you take a photo today you will see yourself differently.
The problem is that in your mind there exists a photo of you who is humourless, self centred, annoying, mean, etc, etc. And you constantly think thats who you are. So you feel you need to change your personality, of course you do!! Because you relate to yourself like that, fixed in time, thats how you will feel, but this image you have of yourself is nothing more than your imaginations cruel deception.
If you held in your mind a kinder photo of yourself, like the one where you are funny, kind, confident and you have been all of these, then maybe you would actually not want to change who you are by changing your personality?
You dont need to change your personality, you need to change how you see your self, this photo in your mind. You have given love to others, you have been generous, warm, gentle, friendly etc yet these photos have been put in the album and filed away, within your mind.
You can make a list as long as your arm and study it trying really hard to be the person you want to be, yet, that person already dwells within you, you need to see that person, then naturally without much effort at all, everything good will come to you.
There's nothing 'You' need to change, except how you see yourself, which is changing all the time, so accept it.
Jack