General Expectation

I am new to this forum but wanted to find an outlet for some past encounters. I wouldn't write it as anything serious per say, I just have been consumed throughout my entire teenage years with a tug-of-war between people's expectations of me and my natural wants. Despite very supportive parents, I was initially confronted with unwieldy expectations to keep an average performance grade of 85%. Though I managed to find a way out of this, I now think that I have never really left that part that demands external validation behind. It is quite unnerving because I close up to people if I disappoint on such matters. I am scared of the fact that I am no more than an aggregate of my marks.
I feel like it is a never-ending marathon where the finish line just keeps on moving away from you. It is like chasing an imaginary goal but I wanted to know if anyone else experiences similar encounters. Like, I don't know where that expectation is coming from and unless I get that validation, I stick to myself and away from people.