Friend being strange

I'm going to start my third year and I am going to be working on a final year project (FYP). From the start I've always been mentioning to my friend group how I've wanted to do a project with either my Personal Tutor or this other lecturer I get along well with.

My friends were talking about optional modules too and when I asked one of them about what their choice was for FYP, one of my friends said she hadn't researched it and didn't know. They then asked me about it and I told them my choices, my friend who just admitted to not knowing what to do then suddenly said she wanted to do the same as me. (She has a habit of copying work and making others do all the work for her. )

I don't know if we can both do the same project but I jokingly responded that I should hurry up and email the lecturer for my project choice, she got offended and responded with 'wow, is it like that then?' I told her I was wanting to do it for weeks (wanted to do my exams before submitting my choices) and that I was already researching on it, I didn't think she would ever be interested in what I wanted to do, because her degree specialises in an entirely different topic!

I don't know if I'll even get it, but I found it really unreasonable that she suddenly became like this. What are your thoughts?