I have a question that I been wondering about

[2naSalit]

3. It depends on

a number of things. If your grandfather is Hawaiian and you know his lineage, you may find that, for many aboriginal groups 1/4 qualifies you as being "of" that group/tribe/clan. In some American Indian groups 1/8 is enough to be considered a member of that group. So it depends on what that group uses as the qualifying amount of provable lineage and whether they are "recognized" by the US government. The government doesn't recognize all the tribes/clans which actually exist but that is not always the case with the actual group. So it could be that you would be considered a "first American".

It would probably be good to know what lineage your grandmother/his mate was too.

You can inquire about that through the State of Hawaii, I think, since it is a group that is recognized, again I think.