Yeah I got to agree with most of this.
So in a way can we say, lets not tell others our achievements? How many times has the odd person who's had great grades from school or whatever, a guys some out with, 'your (inserts bad language) clever dude' in a deceiving and non-supporting way to get the guy who got the good grades to think of him/her self as big headed........It's happened in the past when some people just want to hide their true self, so they can shine in the foreseeable future. So does this mean we shouldn't regularly keep family, haters, friends updated on our success?
I remember talking to somebody about this exact same situation and the guy came out with something which made perfect sense to me at the time (Il try explain what he said as best i can.)
He said that when we do things, rather then tell everybody who cares to listen, you can inform the person by actions. For instance, going back to your driving example if you was to be seen driving around etc, your mates would assume you've passed your test, and being admitted to a top uni college illustrates your grades. This way your seen as humble and not a show off. After all, all of our achievments are blessing from maharaaj, without his help we wouldnt achieve much if anything at all:
Kabeer, nothing is mine within myself. Whatever there is, is Yours, O Waheguru Ji.
If I surrender to You what is already Yours, what does it cost me? ||203||
so in a way, our achievements, are not ours at all!!
hope this helps