Normally it's a sign of disrespect to refer to people with "az", but in this structure there's no alternative to it ("ő" just wouldn't work), so it's absolutely correct. :)
I don't understand what "az" means at the beginning of the sentence. I wrote "A nehéz, ami a japán gyerek elött van," because nehéz starts with a consonant, but that was not correct. I have a feeling that "az" doesn't mean "the" here - does it mean "is"? I'm confused.