So I was in Dawn Star I just walked out of The Mortar and Pestle minding my own business and got attacked by some thugs hired by some hagraven named Moira, I never started the quest "A night to remember" and she called me a theif I'm just a honest merchant :3

So the question is can I stll do the DB quest to kill her?

Who?

http://www.uesp.net/wiki/Skyrim:Kill_Beitild

OP, no idea. I presume the quest just won't be given to you by Nazir and replaced by some Radiant kill.