I have a colleague who is competing for my work, wants to be in all my meetings, even wants my office. I'm finding this very distracting - is it better to give in and let her have what she wants or risk causing conflict by pushing back?
If she convinced your bosses and if other people are OK with this, then it's only your problem. You can get used to this, or change job. It sounds like this went on for a while, and you might want to get some fresh air somewhere else. If she's as good as it seems she will either be promoted or headhunted, so she might become your boss or leave the company. In any case, do your best to be professional and try to understand what motivates her, maybe you will learn something and improve your own work in the process.