What spicemonster said. Assuming you are leading the project, or at least that she is not, she doesn't get to choose who presents this project to the Board.
I think the telling thing in your OP is that you say she 'is doing a paper for the next Board meeting'. Who says she is?
Do you mean she went to the chairman to ask about his participation and he asked for a paper to be prepared for presentation at the next Board meeting, and she has announced to you (leading the project) that she is doing it? Assuming she isn't leading the project then it is for the person who is doing so to decide who is the most appropriate person to prepare the paper and who is the most appropriate person to present it.
She may well be the best person, and if she is, that's fine and should be acknowledged but what needs to be sorted is the relationship between you if she thinks it's ok to announce that she 'is' doing it, rather than asking if it is ok if she does it.
So to answer your question, YABU to be fed up that someone comes in and presents it if they are the right person to do so; YANBU to be fed up that she assumes she can say who does what, and that's what needs addressing. If you are leading the project then you can and should just tell her.
If you are not, and you just happen to think you would be better (or someone else would be), you need to speak to whoever is leading the project without sounding paranoid and whingy, which will not be easy, assuming this person is ok with the arrangement.