Of course your unsure even i was when i first went there admittingly.
Well first off welcome to the forum, hope you have fun here.
Before i knew an Indian man who worked in Japan for a year and he loved it there and had nothing but praise for it but he had perfect english.....and that was before 9/11 so things might change. Considering your from Turkey your not really middle eastern either your a part of Europe now so if anything see yourself as an example, many Japanese people have never met someone from Turkey so maybe you can be the one to educate them better making many misconcepts disappear. Im glad your not a muslim too because trying to be a good muslim in Japan i imagine would be very, very hard. There are not mosques which i know of and of course no halal meat to be bought, amoung many other things