I'm sorry your protagonist is giving you trouble!

I'm also starting with a fresh idea, and I have exactly the opposite problem (as usual!). I know my main character inside and out, but I can't for the life of me figure out what sort of plot I want to put him in. I have an idea and a vague outline of what I need to happen, but I'm not getting far, and I feel like the plot, at this point, is just a pale excuse for my character to exist. I'm working through making a setting database right now, but I don't know my world well enough to give it the detail it deserves.

On the subject of getting to know your character, have you tried choosing an extreme situation and trying to put her into it?

For example, you could write her first or most vivid memory, a scene in which she interacts with the person she loves the most, or a scene in which she experiences profound loss or even dies. They might now be used in your book, but they will reveal a lot of things about your character! (Disclaimer: Many of the ideas I've just mentioned are examples of things that writers have to put their characters through for the "Invalid Item"  contest.)

Choosing any extreme or formative event can help you learn about your character.

Writing a scene where your character interacts with a person they hate or someone with opposing views may also help. (For example, you can learn how your character responds to anger. Is she calm? Does she react violently? Is she aggressive, or passive-aggressive? Is she willing to listen to and consider opposing views, or will she steadfastly ignore them?)

I don't know if this will be any help, but I know it's helped me in the past.

Good luck!