What do you think of me always being less nice to a girl when she calls me a bro?
Do you not like her?
Yes, she is a really nice girl, but she is a bit too familiar with me.
It can feel weird to have people be too close to you when you just met, so it is understandable why you would be upset. Just let her know what you are comfortable with and maybe things will work out.
I know, I'll just be more careful and maybe change the subject whenever she calls me a bro and then we'll be fine.
Yeah, it is smart to just work through this issue if you don't care too much about it. It is important for both of you to show good manners towards each other.