No way.
Sure, they may be really easy to read, as in she wont need to get a dictionary, but they are in no way appropriate.
Think about the first book where he has to physically restrain himself from biting her?
The second book where she almost gets attacked by those guys? Or when she purposefully injures herself so she can hear Edward? Jacob's change?
The Third book where Bella wants to be sired but Edward wont do it unless she marries him?
The fourth book, are you kidding me? With that pregnancy scene?
She doesn't know anything about relationships she she'll think Bella dn Edward have a perfect relationship and that's how they are supposed to work, that her future boyfriend will be Edward.
Plus, I think the books would confuse her (plot wise, as my niece is 7 and I have to explain just about everything to her).
It would be irresponsible for you to let her read those books.