as long as your first author thats all that matters! and reason you have to have the other authors, is because (im assuming) you didnt do everything on your own, you got some help from the others that are listed.
i have had one paper published, and i am the first author. and then my supervisor is last author. supervisors always want to be last, cause its good for THIER cv and career. and then the other authors, are people that actually contributed to my study. such as the statician and the pathologist, or what not.
but i get to be first author, because I did the study and i wrote the paper. and thats all that matters!
first authorship, is excellent , so well done you