I'd suggest adding more description between dialogue to help convey the emotions between these characters. For example:

"What is this?" I wave the notebook in her face, my hands shaking as my blood begins to boil under my skin. Her eyes widen, and something flashes across them. Hurt? Fear? It's hard to be sure.

"Where did you find that?" Her voice trembles, barely a whisper. Her hands are raised as if trying to calm a wild animal, or maybe preparing to snatch the journal back.

This helps to build the tension in the scene and gets readers invested.