You're not a member of a tribe, not involved in Native American heritage. For the first seventeen or so years of your life, you've checked a box for something other than Native American when asked about ethnicity. I think you already know that what you're doing is dishonest and that you're only doing it because you think it will give you an advantage. Just because someone has a great great grandparent who was a certain ethnicity, does not necessarily make them that ethnicity. For example, let's say that someone is black, but they just discovered that their great great grandfather is white. Should he or she claim that he/she is now white? Physically, they appear black, but they're very interested in finding out more about their white ancestor. See this (long) previous post, especially post #34 by an admissions officer. Could you get away with this? Possibly, depending on the school, but do you want to take the chance that you will be discovered and that it could hurt your chances for admission?
Am i a minority?