Of course,it's a mere amusement between friends in leisure time.Whatever the result is,one's social status won't change because of it. And I do know more about English now.At this point,it seems not bad.

Then it's highly likely that "U" means "upper class", but one should take these quizzes with  a pinch of salt.

The quiz measures it according to one's lifestyle.One of my friends recommended it so I just took it.

It depends how the quiz is being scored doesn't it?  In my school a "U" was never a good thing.  Exam marks from top to bottom were A, B, C, D, E, F, U! :/  Sorry!