I was thinking about Harry Potter. Then I was thinking about it more. Hence thoughts about autistic Hermione. No, she doesn't have to be read as autistic, and I'm not going to argue that she must be read that way because it's not so. I do read her that way, though (People told me I was just like Hermione for years...) And I am having thoughts.
Trigger Warnings: References to major bullying and possibly being suicidal.
Imagine Hermione speaking on time, maybe even early, but her pronunciation is off in ways that get her sent off to speech therapy anyways and she hates it because it's so hard to get her mouth to move in those ways. Once she learns, though, she hasn't got any patience for the people who didn't have to work like she did and get it wrong because they just don't care. Her classmates figure this out and use it to trigger meltdowns.
Imagine those meltdowns (and the ones caused by other bullying, and sometimes even the ones caused by plain old sensory overload) meaning that the teachers are kind of scared of her. The fact that meltdowns are one of the big times when accidental magic comes out doesn't exactly help here. They're terrified of her. So are her classmates. Not terrified enough to stop bullying her and triggering the meltdowns, though. And like Neurodivergent K pointed out, teachers punish the Behavior, but not the Antecedent to the Behavior (huge trigger warning on linked post.) This gets Hermione in a lot of trouble.
This goes on for a few years. Now it's the summer between fifth and sixth grade, and Hermione just turned eleven. Her parents are fighting with the school yet again to keep her in typical classes because they know she's smart, they know she doesn't belong in special classes (they're kind of Aspie elitist even though Hermione isn't really an Aspie, they just want to think she is. Yes, this is a source of tension, though Hermione never brings it up. She knows full well that people thinking she's Aspie is the only thing barely keeping her in the slightly less boring classes.) In the middle of that battle, a letter from Hogwarts arrives. Her parents see it first, and their initial reaction is that it's a scam to get them to pull Hermione out of school. They don't fall for it, they're convinced that the instant they respond it will trigger some sort of automatic dropping her from the regular rosters (true) and then it will fall through itself (false.) They decide not to tell Hermione, because they want to protect her from the lengths people will go to to exclude, at least for a while yet.
Then Professor McGonagall shows up at their house. This woman from the letter shows up at their house and Hermione's parents are terrified because this person trying to get out daughter out of the schools is at our house. Hermione starts out confused, since her parents didn't tell her about this latest development, then she's scared of McGonagall and angry at her parents for not telling her. Somehow McGonagall convinces them that Hogwarts is for real and that they're not just trying to yank Hermione out of school and that they didn't even know that was going on and why were they trying to do that anyways?
McGonagall is kind of confused because she's never dealt with this label “autism” before (there are autistic wizards, of course, but none of the ones coming through Hogwarts have been diagnosed before) but the magic that tracks the accepted students can't be fooled so she just goes to work figuring out how to make everything work. Hermione's hair somehow manages to become a major issue- she needs the weight of it for sensory reasons, she can't do brais (also sensory), and she hasn't figured out the motor skills for brushing it herself yet. This actually has Hermione's parents really worried. Hermione's sort of assuming there's a spell that will take care of it, and there is, but it's not one you'd usually expect a first-year to be able to do. But this is Hermione, and she gets McGonagall to at least try teaching it to her, and it turns out she can do it. Since McGonagall thinks it's a bit odd for an eleven year old to still need her parents brushing her hair, she winds up giving Hermione permission to use just that one spell outside of school even though she's underage, and she makes sure the Ministry knows. That's the spell Hermione was talking about on the train, by the way. She didn't want to say so because she's learned what happened when her classmates know.
But before we get on the train, there's more. She memorized all her books? Yes, she really is that interested, but that's not why she started. She was scared. What if they decide they don't want me at Hogwarts either after I'm there? I won't be able to go back to regular school, they won't take me, I can't screw this up. So she decides she's going to memorize all her books. It turns out to be easier than she thought because all of this is just so interesting, but that's not why she decided to do it. She'll let you think that was why, but it's not.
Now we go to Hogwarts. We already know Snape's bigoted- we know it from how he treats Muggle-borns and werewolves. He's an abusive bully too- see Neville's boggart being Snape, seriously. Now we've got a developmentally disabled Muggle-born. That's even worse. So instead of being understanding about her being autistic, he decides to take advantage of it to push all her buttons and then blame her for it. And of course, the Behavior gets punished, but not the Antecedent. That's even more true when a teacher is the Antecedent (still huge trigger warning on link.) It doesn't actually help that she's smart. If she were average, he might get sick of it, but she's top of the class and doesn't dare let anyone forget it because she's still scared they'll send her away like her primary school wanted to and she's pretty sure they can't threaten Hogwarts with a lawsuit. Maybe he doesn't get that's why she makes it so clear. He probably wouldn't care anyways.
And of course, the oh-so-famous line, “before we get killed, or worse, expelled!” An autistic student who's pretty sure there's nowhere else to go might legitimately think expelled is worse because if you're dead you at least don't need to deal with the fact that there are no more options. There are reasons so many school-age autistic people get suicidal, and the thought of being pushed out of school again (the only school where she's ever had anything resembling a friend!) could well be enough to push an autistic Hermione in that direction. Not such a funny line anymore, is it?
Over time, Hermione gets more comfortable with the fact that they're not going to send her home in disgrace over all this stuff. Being friends with The Boy Who Lived probably helps here- it's a big priority to keep Harry safe, and Hermione does save Harry and Ron's skins quite a few times over the course of the books. Her first reaction when she wakes up from being Petrified is still that having missed so much class is going to get her sent home, though. That's why she stayed up as long as her body would take (brewing alertness potions herself once Madam Pomfrey wouldn't give her any more) to get caught up for the year-end exams as soon as she was awake. And then Dumbledore cancels them and all that work for nothing?! She's not great at hiding her emotions and we see her upset reaction. Once they don't send her home over the safety issue of her getting Petrified or over all the class she missed, she's actually a lot more comfortable with the fact that she's not getting sent home. She's kind of wondering what it would even take to get expelled, since the only example she's got of a person being expelled is when everyone thought he'd murdered someone. She never gets completely comfortable that she's not getting kicked out and sent home, even after she's married to Ron and has kids and is the director of... I actually forget what she was the director of sorry, but the fear is in the back of her mind, not the front. Not gone, that kind of thing never goes away any more than traumatizing stuff she dealt with in her time at Hogwarts and in the year she spent running around for Horcruxes does, but she's mostly past it. Mostly.