Grace, I think I can identify with your situation to a large extent - I have BPD myself, suffer greatly with anxiety, and I've come to suspect that I might also have ADHD (which basically didn't exist when I was a child - I'm 42 now). I was also academically talented - my teachers at school saw me as an Oxbridge candidate, and before dropping out of university (more on that below) I was well on course to obtain a first-class degree (albeit from a former polytechnic).
And I've made absolutely nothing of my life - my BPD and whatever else 'won' in the end; I'm currently unemployed, and haven't worked full-time since 2008. Which isn't to say I believe you'll end up the same way, not at all... but my experiences have taught me a few things that perhaps it'd be worth you - and any other aspirational younger person with BPD - thinking about.
More optimistically, I can already see one positive sign in comparison to myself in that your applying to top institutions means your focus - and confidence - in this context have already lasted longer than mine did. I wasn't interested in Oxbridge for several reasons, one of which was that - due to my lack of self-confidence - I wasn't up for the competitiveness of those institutions' selection processes. As to focus... again, long before the time came to actually make applications, I'd become distracted by... extra-curricular activities... and so my studies - and therefore future career - were secondary priorities.
I mentioned above that I dropped out of university... those damn 'extra-curricular activities'. Short version - I fell for someone, she didn't fall for me, she decided she hated me for falling for her, and I fell apart. Completely. This
is relevant, because the intensity with which people who have BPD can fall for others, and the completeness with which failure in this context can take us apart, can lead to anything and everything else we're doing at the time being completely derailed. Indeed, losing jobs - and generally having to 'start over again' - in the aftermath of BPD 'episodes' is a common symptom.
An overall idea having BPD has given me is that the niche we come to occupy in life has less to do with what we're capable of at our best, and is more the result of what we're still able to manage at our
worst. We'll always hit low points during our adult lives - all of us, BPD or no BPD - and if we're unable to
do anything at those times, it makes us unable to
be anything. As I've found from personal experience, employers don't really have much patience with repeated bouts of being so wrapped up in your own distress that you can't concentrate on anything external.
The closest I've come to sustained stability has always been when I've distanced myself from anything to do with relationships. I'm not saying you should become a nun... I would strongly advise however that you be extremely careful who you allow to get close to you in this context. Certainly don't use shit like Tinder... let yourself be viewed like a piece of meat and people will treat you accordingly. Those with BPD tend not to have the luxury of sufficient emotional resilience to handle being treated so disposably.
I don't know if this is possible for you, but I have found the best motivation is to find work you are genuilenly passionate about. Trust me it makes motivation much easier when you are passionate about your work. Unfortunately while ideal for a lot of people this isn't really possible in their situation.
This is also very good advice in my opinion, but perhaps more from the ADHD point of view than a BPD one. Probably the biggest single issue I've had with work is that of boredom... from the very first bit of work experience I had when I was 15, I struggled to cope with the repetition intrinsic to so many jobs. It's such a big switch from education - in which classes and lectures are never more than a couple of hours in length - and I've never been able to make the adaptation.
However, I've never been able to find a job - or general line of work - that I have any real 'passion' for... if I can do so, I think that's the best chance I have of not becoming bored - and consequently depressed - in any given role after a short amount of time.
