"What do you need boy robes for?" inquires Madam Malkins.
"I'm sometimes a boy," the girl explains.
"What?"
"Look—"
"But if snakes are sapient—and don't look it—what about other animals?!"
"… I am not a huge fan of meat and don't eat that much of it anyway so it's not a huge problem for me."
"Well, I don't care about food much, but that's beyond the point! Snakes eat other animals! And are eaten by other animals!"
Pause. "They are but I don't think it's very easy for you to stop that, on a large scale? And other wizards don't seem to care about it as much as you so I don't think they'd really want to help."
"Yes and that's a problem—I don't even like animals—or they don't seem to like me—but if animals are people—"
"… It's not really one you can solve right now. You have – four? – days until you go to school."
She grimaces. "I can at least figure out whether other animals are in fact sentient!"
"While at school? Yeah. But – I'm not sure if they are sentient or not, it might just be a magic thing. I'm not sure people have looked into it."
"Very rarely people have it? I think it's inherited, they just have the ability to talk to snakes even though they didn't learn it separately, it's kinda Slytherin?"
"Slytherin being... one of the Hogwarts Houses? Why is it? And do the snakes respond? Do they actually hold conversations or?"
"Slytherin is one of the houses, yeah, with a – patron animal, house animal or whatever – of a snake, green. So that's why it's Slytherin. I have no idea about conversations, I don't know if they're smart or just respond to basic questions or what."
"Okay... We need to figure that out, have you gotten your books yet?"
"Nope – uh, mum's got my wand and clothes, still need to go to the apothecary and bookshop and get a telescope – I think mum said she'd get that and the scales – then probably an owl? … Probably also with mum."
Onwards to the apothecary, then.
"I didn't get my wand yet. Wanted to leave it for last."
"'Cause it'd be tempting and we're not allowed to use it before school."
"Ah." Pause. "Well yes but it's a law, I'd expect that to be discouraging enough?"
"It's not a law they do anything about here in Diagon Alley. Not if you can look like an adult like, oh, certain metamorphmagi can."
"… I think it might be a magical thing, based off who owns the wand, not whether you look like an adult," he says. "I've heard that people do sometimes get warnings at home?"
"The Deputy Headmaster said it was about doing magic while underage while unsupervised by an adult."
"Huh," he says. "They might have changed it recently or maybe rumours just aren't perfect."