AITA for telling a coworker not to go through my notebook after she read and repeated what I wrote?

I work in a small office where most of us share supplies. Nothing is officially assigned, but people tend to respect what belongs to who. I keep a specific notebook at my desk where I write down ongoing tasks and ideas. It is not anything confidential, just personal organization that helps me stay on track.

Last week I came back from lunch and noticed my notebook had been moved. At first I thought I had just forgotten where I left it, but when I opened it I saw a few pages flipped and a sticky note stuck inside that I definitely did not put there. Later that afternoon, a coworker casually mentioned something I had written in the notebook as if it were common knowledge. That is when it clicked that she had gone through it.

I felt uneasy about it. Even if the content was not private in a strict sense, it still felt intrusive. The next day I spoke to her and said I would prefer if she did not look through my things without asking.

She seemed surprised and said she thought it was fine since we all share materials and she was just trying to find information related to a project. She also said I was overreacting because it was just a notebook and not anything sensitive.

I am not sure if I handled it the right way. I did not want to let it slide because it bothered me, but I also did not intend to create friction.

Am I the jerk for calling her out on it?