Listen, she is starting to have regrets as she's realizing she's about to loose you.
That's why she's trying to prolong this whole thing, because she's frantically searching her mind for a solution, trying to decide what to do.
In her head it goes like this: "He wants to be exclusive, but I don't! What do do? But I don't want to commit right now. It's not a good idea to commit right now. But I still like him! What to do, what to do?!"
I'd say; meet up with her and see what she has to say.
But do NOT change your standpoint. You've made it perfectly clear you want a relationship, don't change your mind about it. It will make you look weak. Don't let her jerk you around.
Listen to what she has to say, but listen to your heart.
You want someone who can commit, and unless she has something quite extraordinary to say, if she still says she can't commit but doesn't give any particular reason, you should stay away from her.
Stand your ground, fellah!!
"If you love life, life will love you back."
Arthur Rubinstein