Back in the golden era of baby-boomerdom (1960/70's) there was only one important decision a teenager needed to make and that was what to do after school. I'm obviously referring here to privately educated "privileged" individuals and not to the riff raff who emerged without so much as an O level from the state school system. They either went into some dead end job or turned to crime.
The privately educated privileged, depending on their A level results, had to decide whether or not to go to university and since all their friends would be going to university chances are they would too. In fact, not going to university sent out a strong signal that you'd probably either failed your A levels completely or scraped through with poor grades.
Parents with children who had just taken A levels and weren't going to university had some explaining to do at the golf club. Where I grew up in south London nobody wanted to be known as the parent of a thick child. If you did flunk A levels there were two face saving possibilities. One was a crammer school and a second attempt the following January and the other was a year spent overseas doing voluntary work.
Those who did get good enough grades for tertiary study would have already applied to several universities before taking their A level exams and would have been given provisional acceptance. The choice of university was vitally important and depended on all sorts of factors such as the distance from home (the further the better), the ratio of women to men and the number of good pubs and clubs in the area.
Southerners would be traditionally wary about going to somewhere like Durham for example because they probably wouldn't understand a word the locals were saying. Northerners, on the other hand, enjoyed applying for places like Exeter because they hoped the civilising influence of the West Country would smooth some of their northern rough edges.
The posh and well-connected went to Oxford and Cambridge, just as their fathers and grandfathers had done and read Politics, Philosophy and Economics before going into politics. The really clever kids also got into Oxford and Cambridge, hopefully on a scholarship. The rest of us were scattered across the country, mostly at universities that were far removed from the Brideshead Revisited romanticism of Oxford.