Choosing based on friendships proves DD isn’t ready to make adult decisions.
I think it shows that she has other priorities, which is fine. Regarding friendships as important is not a juvenile decision - she has got to live there for years and quite rightly does not want to waste 3/4 years of her precious young life on something that she feels unhappy with. So many students are utterly miserable at uni which impacts on their results, and this lass realises that friendships are important to her. Self-insight is good. She has grasped what she feels she can cope with and Edinburgh feels a step too far to her at this moment.
I do not think this is all or nothing - that if she chooses Kent she will be burning her bridges as regards future choices. She will find her route to where she wants to be. The choices she has are broadly similar and will get her to the same goal in the end.
She may of course completely change her mind about what she wants to do - students of 17/18 are very young to be deciding what career they want.
I jumped ship on my career after a couple of decades and went in a whole new direction.
I feel concerned about this narrow race that is fuelled by parents and teachers: do GCSEs now, do A-levels now, go to uni now. Where do they get to develop and grow as people if they are just cramming their heads non-stop?
If she is bright enough to get these good A-levels and to be in line to study such a difficult subject then she will find her way for sure. Can you imagine what the scenario might be like if she capitulates and goes to Edinburgh and it does not work out for her there? She will be a long way from home and feeling annoyed with her parents for pushing her in a direction she did not want. No gains there for anyone ......