I wouldn't say I'm presuming Asians are nerdier. Since I'm a nerdy Asian, I can only speak to the type of people I know. What I meant is: "if I were in school with only people who were like myself."
"As a nerdy Asian, if 50% of my classmates were nerdy Asians,"
with
"As a nerd, if 50% of my classmates were nerds,"