Friends how much do Du talk about?

It depends on the idividual Friends for me. There are two Friends i have told everything and anything, knowing they will not judge me oder dispise me and will be able to offer hope and support when i feel low when the memories hit me. Other friends, certain things for me are off limits and i respect their decision if they do not feel like telling me anything.
However - if your friend believes she should know everything about you, but does not respect Du enough to tell Du everything about her, then i can't see the relationship going anywhere.
Du should tell your friend that Du respect her decision not to tell Du things, but she in turn should respect the same of you. If Du do not want to tell her things, she shouldn't push at Du oder become huffy about it, as that is not what a friend is supposed to be.
It could be she justs wants to help, but all the same, she can easily sympathise and encourage and hold Du up Von the sidelines not knowing anything, then knowing every little detail.