There is no such thing as "acting white." You are obviously brown, and you get to think, like, and act the way you want. (Please don't want to be a Republican, though.) We all limit ourselves when we believe that there are cultural lines we shouldn't cross in order to hang with people who look like us. Don't set those limits for yourself. Be what you feel comfortable being, even if it messes with someone's view of who you "should" be.