Look, I find ancestry/geneaology as fascinating as the next guy, but I am not "nearly half-Irish ethnically"or whatever just because three of my mom's grandparents were descended from 19th century Potato Famine refugees.
I am American. My parents were Americans. My grandparents, all Americans. My great-grandparents were Americans as well. Ok, I think I had a few great-great grandparents who were born in Switzerland on my paternal side....
The relevant part of my ancestry is that they were all light-skinned Europeans.
Okay. Some people feel differently and enjoy identifying themselves as a type of non-American ancestry.
As for me, I'm mostly English. Some German.