If you are you would know from your mother or father's oral traditions. This is something that is not hidden or forgotten by any of the royalty.
I am of the royal Yi family and it is on the immigration papers of my mother, the U.S. government put that informantion on the paper work at the time of the immigration.
Check the paper work from the last immigrant, see what it says.
Also the name of your father or grandfather or so on would tell you just by the name itself as that lineage is preserved in the names of the males.
You might be related but if you are of the direct lineage you could find that pretty easily.
Good luck keep checking and ask your relatives.