Asking to present paper as first author, when the second author's travel has already been booked I recently published a paper at a technical conference in computer science as the culmination of my bachelor thesis. I'm the first author for it, and my 2 supervisors are the other co-authors.

I pursued this thesis in another country A, and after completion went back to my home country B. This paper recently got accepted for oral presentation at a conference to be held in A. Upon requesting for funds to attend the conference, my supervisors said that this is not possible since the conference is local for them and thus it is little to no expense for one of them to go and present the paper.

Since this is my first scientific publication, I am very excited for it and wish to attend the conference to present the paper. I searched around a lot and managed to scrape together some financial assistance from various sources. In spite of this, I will still need to pay a large amount of money from my own pocket.

Since this requires a large expenditure from my end, I wish to confirm with my supervisors whether I will get to present the paper or not. I think that since I am the primary/first author, the opportunity should be mine – but I'm not sure what is the norm here. Is it a reasonable request if I ask my supervisor to present our paper since:


I'm the primary author.
I'm spending a lot of my own money to attend the conference.


The primary issue is that one of my supervisors has already registered for the conference – so I fear that they may cite this as a reason for not letting me present the work. Any thoughts/comments?
I think it is certainly appropriate to ask and wonder why you hesitate to do so. I think that a note that you are able to attend and that you would like the opportunity to present the work and that it would be a boost to your future career should be received positively. 

Having registered for the conference (the advisor) should mean little or nothing in this situation. Whether it is good politics to demand your right to do this is a matter of personalities, of course.  

But the fact that you are spending your own money likely won't count for a lot. Your presence at the conference should, however arranged, count in your favor. 

But, yes, it is reasonable to ask, and I think it would be unreasonable for the advisor(s) to refuse you. 



I'll also note that there are a lot of reasons to go to CS conferences beyond presenting something. Your advisors should recognize this. They haven't "wasted" money if you present in their stead. There are normally a lot of ideas floating around and a lot of interesting people to interact with.