Are all women closed off like this? Please explain.?

It's not just girls, I've known a heck of a lot of guys (like, almost all of them) who keep their inner most thoughts and emotions bottled up inside. Even if they claim I'm their best friend forever they still never are able to express themselves. Sometimes, it's a problem with vocabulary, like they just don't know the actual grammar or words that will exactly mean what they feel. But mostly, it's just a lack of trust and that can start way back in childhood. If a kid is never listened to when she tries to express herself, if she's always told to be quiet (meaning her opinions and thoughts don't count), if she's smart she'll learn to shut up, even when someone says they want her to unload. All you can do really is be there for her, always let her know you are available if she ever wants to rant or dump or just talk openly with someone. NEVER ever ever judge her, never say things like "well, that's just stupid" or "you don't know what you're talking about" or anything else that'll tell her you also think she needs to shut up. And, possibly, she may never come to trust you (maybe not anyone) enough to open up because opening up exposes her soft underbelly, her weak spots. Perhaps you could start a sort of penpal thing going, writing letters to each other--some people often find writing things down a little easier then actually saying things face-to-face. Maybe she has a blog you could ask her if you could read some of her stuff (her blog site might allow her to determine which of her writings she wants to allow you to read and which ones are totally off limits). There are women who will just tell you every single thing that goes on in their lives, in their minds, to the point where you wish they'd learn some discretion and keep some things privately to themselves. And sometimes after a woman determines she can trust you completely, she'll start telling you her private thoughts and feelings--but there is a trust issue you have to overcome by proving you are worth her trust.

Introverts don't like to discuss feelings, because they find the subject to be boring, and they get nothing out of it. If you want to date an extrovert, then why not go and find someone compatible with you, instead of trying to change an incompatible person into your dream date?