Autism is one of those disabilities that paradoxically receives a large amount of awareness but also is continuously misunderstood - particularly in the education system. It feels that, to the ignorant, autistic people are either seen as socially isolated savants or severely learning disabled*. It's extremely common for allistics (non-autistic people) to feel the need to pigeonhole autistic into a category, despite autism being a 'spectrum' (although, not a linear one - and, to be honest, all disabilities exist on one spectrum or another, rather than being discrete types).
I think this continued lack of understanding of how autism can work - and worse, the insufficient amount of autistic people working in disability support - is certainly the reason I have struggled as an autistic student and likely the reason a lot of my fellow autistics also do.
I wasn't formally diagnosed as autistic until my First Year of uni in 2014 (after a diagnosis journey of about four or five years), but I have been autistic all my life. Thus, I had to spend my entire school career (i.e. my formative years) learning things that were being taught through an allistic lens. Everyone learns differently, autistic or not, but a lot of the ways that allistic students learn are in particular inaccessible to the way neurodiverse people process information.
What ends up happening, therefore, especially for an undiagnosed autistic, is we struggle to process the information our peers have no issue doing, but don't understand why and it's never explained to us, and so we internalise that frustration - and it becomes self-directed blame. Especially if, like me, you were one of those 'gifted'/high achievers during primary school - "I know I'm not unintelligent, why am I struggling so much now - was I never that clever, am I actually not as good as people think I am, am I just lazy???"
And then finding out you are autistic for sure at the age of 19 doesn't suddenly fix anything. It's not as if I can suddenly switch over to autistic learning methods, because I was never taught those. And even when I access University support, it's not exactly helpful. I often get asked - well what methods work for you? I don't know! That's the point! If I knew, I'd be trying them.
This above quote is something that needs to be drilled into the minds of everyone involved in the education system. Frankly, we need a revolutionary move of completely dismantling the institution and rebuilding it from scratch to be inclusive. Patches don't work - rather than teaching all kids as if they were able-bodied and then providing support to disabled kids that only serves to confuse us, we need to teach all kids the same way that is inclusive to both. It's definitely possible.
Hopefully one day it'll be likely.
* As a terminology footnote - the UK 'officially' uses the term 'learning difficulty' to describe disabilities that are considered to impact on one's ability to process information - this tends to refer to disabilities like dyslexia and dysgraphia and others that come under the neurodiversity group. This author considers the term euphemistic (i.e. worded to avoid the word 'disability') and therefore prefers the US wording of 'learning disability', which in the UK is used instead to refer to neurodevelopment disorders such as Down syndrome (the US (and I) uses the term 'intellectual disability'). This article will therefore, as per my preference and self-identity, use the American terminology for these two.