Can I reject a girl I'm not into?
Why do you want to reject her?
I don't think things will work out.
It's fine to not like someone that likes you. It's good to be honest about that.
Yes. I think I'll limit my social circle and stick to the people that don't think they are superior to anyone.
That is totally find. The sooner you tell her the better things will be for everyone. If you lead her on because you are trying to be nice it will only hurt later if she thinks things are going great.