I have an awkward situation at work and would love to hear some advice.

Basically, the question is this: if you proposed a paper to a conference, and it gets accepted, should you invite a colleague who didn't work on the proposal to present with you? (Assuming this colleague had a small role with the project discussed in the paper and will be at the conference.)

Here are the specifics:
I'm about two years post-MLS, working in an academic library, and just starting to get more active professionally. I submitted a paper proposal to a library conference, based on some projects we've implemented at the library. High chance of rejection, but I can only get travel and conference funding if I present, so I went for it. I should hear pretty soon if it was accepted.

In the meantime, I just submitted my application for university funding to attend the conference (again, contingent upon getting my paper accepted).

My supervisor, who normally I really like but who isn't active at all professionally, sent me an email letting me know that a colleague in our small department will definitely be attending this conference with other funding (she's not presenting). The email said suggested we do a "tandem presentation." She said even if my paper/presentation is done (which it isn't), I should ask her to join me. This colleague definitely could have submitted a proposal herself but didn't (this is her first professional job and she hasn't yet forayed into conference-land). I think my supervisor is trying to help out our colleague. But I thought it was an inappropriate request from my supervisor.

I talked to my colleague, and we're fine. But I haven't responded to my supervisor. The issue might go away if I don't get accepted. But I'm still wondering how to navigate this with my supervisor. Although my professional development activities are linked to my job, I also feel like it's a bit independent of my job. For example, I've already used mostly my own time to work on my proposal and only a bit of work time. Also, I really like presenting... and I'm not inclined to share this. Then again, this colleague has been involved with this project, though not in a leading role.

Am I being selfish and territorial? Or was my supervisor out of line?

Thanks for the advice... I'm hardly a veteran librarian, since I'm only two years post-MLS graduation, and this would really be my first national conference presentation. So that's perhaps why this has caught me off guard.