Quite honestly? I just don't 'get' Bella and Edward sometimes. I'm not picking on the SHIP, per se, but a lot of it seems superficial to me, especially on Bella's side. Don't be angry at me, please, it's just an observation, so Elaine, I'm glad you brought up your exasperation with Bella, because I have felt it almost the entire time I've read the series!
I can't help but feel that, perhaps to a great degree, Edward & Bella's love for each other is mostly infatuation.

I wonder if perhaps they are too much attracted to the
mystery of each other, instead of to the
reality of each other? Edward's fascination stems, not just from Bella's scent, but from the fact that, unllike anyone else he knows, her mind is unreadable. Bella is attracted to Edward very much in the physical sense, and the vampirism seems glamorous to her. In no place in these first three books have I read any of her thoughts on the fact that she will have to drink the blood of animals once she's turned. She's just like, "Oh, OK, we don't have to drink human blood? Cool! Kiss me again, Edward." It's like she has shut the grisly realities of the vampire existence from her mind in order to concentrate exclusively on being with Edward. She even minimalizes the incredible pain the transformation will make her suffer.
But the thing I like about Bella, as all have said, she is human. I see an endearing (and sometimes, alarming, in her case!) human failing in her in that she seems to think she is one kind of person, when in reality no one else really sees her that way at all! She sees herself as sensible and independent--but does anyone else? Everyone is always arguing with her, disagreeing with her, manipulating her (and she falls for it every time!), and generally doing all they can do to keep her under control! Yet, to herself, she's sensible.

I think that we all do that to some degree--think we are one kind of person and refuse to admit to our own shortcomings. As people in my neck of the woods would say, "She's good at blowing smoke up her own backside."

I don't blame Edward for wanting her to wait to be turned. She isn't a very strong person (yet!), even though she thinks she is. She tries too hard to please, trying to keep Edward happy, Jacob happy, her Dad happy, etc. That's what tears her apart, and it's also what I feel makes her too weak to be a good vampire. I think she's got a very rude awakening coming in book four!

P.S. Has anyone ever said anything about how Isabella Swan of Twilight and Elizabeth Swan of PotC have the same name? Isabella is the Spanish version of Elizabeth, isn't it? I just thought that was strange...