Nah, I don't think you would be a henna gaijin. See I'm like that too. I get along with Asain people and am naturally drawn to them, but I am a guy so it's a bit different for me, but I have a lot of friends whom are girls.
I have a friend who sounds a lot like you but with different hair and she went over there about a month ago. She said a few people said a few things but she couldn't catch all of it. That was just when she got of the plane anyway. So I don't think it will matter much. :/ Good luck.
