Probably not. In Nevada, parentage/paternity matters are governed by Chapter 126 of the Nevada Revised Statutes ("NRS"). NRS 126.071 states that an action may be initiated by a child, the natural mother, a man presumed or alleged to be the father, or any interested third party, to "declare the existence or non-existence of the father and child relationship. However, the very next provision, NRS 126.081(1), says that such an action "is not barred until 3 years after the child reaches the age of majority." If you are 27, the maximum time for the bringing of such an action apparently expired six years ago.
The next subsection, however, NRS 126.081(2), states that "This section does not alter the time within which a right of inheritance or a right to a succession may be asserted byond the time provided by law relating to distribution and closing of decedents' estates or to the determination of heirship, or otherwise."
So while matters relating to support are probably foreclosed, matters as to inheritance are apparently not -- this may or may not be significant, of course, depending on facts which you do not reveal.
Further information about paternity actions can be located on our Paternity page, posted at http://www.willicklawgroup.com/paternity. You should also consider obtaining a second opinion. On the family law side, I would suggest starting your search with the American Academy of Matrimonial Lawyers, which can be viewed at http://www.aaml.org. You should also find an appropriate probate attorney to discuss your options in that regard.