I feel with you because this is how I experienced all of school
It's still there though, for me though the hinder lies in expectations I set for myself (most likely inherited from my parents). I always hoped I would have someone on my shoulder saying, it's ok to be rubbish, as long as you keep writing, because eventually it will be better.
What you write about is also something that I think is wrong with how it's supposed to be when I was at school. I would most likely be more adept if I was writing about something that I was really caring about, and then getting help with the constructs, identifying them and restructing the text. Not what the teacher picked out.
Maybe there's a middle ground, if the early years are all about getting _your_ flow from thought to paper is what matters, the teacher have a piece of cake hammering down the structures later on, which in turn would make it possible to take on any kind of task. I know there's some work in our schools today, but I'm not that positive about it (since they ignore spelling pretty much). It will be great to read some results from it whenever it appear though.
I strongly relate to that. I never wrote a paper in school without deep stress and lots of procrastination, and I think I only wrote one paper throughout both high school and college that I was proud of, the rest were just the bare minimum of competency that I thought I could turn in without dying from shame. But contra that experience, I've always been a voracious reader of all kinds of texts.
Now that I've had a long time to look back on this (I'm about a decade older than you), I think a big part of my problem was that I never felt like I had anything to say on the topics of those assignments. I never found hidden meaning to deconstruct in the fiction I read, I just knew that I loved how the best authors constructed worlds alongside the characters who belonged in them; but that didn't seem like what I was supposed to write about. I never knew how to write about the non-fiction without just re-stating it. I never felt like I had a substantive extension to the arguments made by philosophers, economists, and political scientists, and I never felt I had the expertise to disagree with them. All of this is to say: my problem wasn't with writing per se, but with having something to write. I'm also not saying that this is a problematic approach to an education in writing, it's just that I was rubbish at it.
What finally helped me was to write a lot about things I know: emails and documents at work where I have expertise in the topics being discussed, and writing about my thoughts privately and with my family.
Maybe your peers in school were like me?