I believe that although your background does help it is more a state of mind. Britain would probably class us as Middle-class but would be at the lower end as my parents rarely earned above £20k each during my childhood. My uncle on the other hand earned in excess of £200k a year by himself, but was always humble about it.
I am very ambitious and will work hard to get where I want and as such financed myself through university by working in the local store. My two cousins did not, they had a free ride.
I took Computer Studies, not only because I enjoyed it but becaue I knew it would be useful.
They took art and media studies respectively, one is now a call-centre worker and the other is out of work. Because they had it spoon fed to them they do not have the drive or ambition and no matter how hard the family tries to tell them they need to work hard they just don't get it.

I suppose I'm trying to say it is more about your attitude and how hard you had to work through your education that determines your success in life. If you got the right attitude, you'll go far