The first person ever to call you a Mudblood is Lucius Malfoy. You don't know his name, of course; later, when you learn it, you will marvel at the irony: this boy is a prefect.
It happens when you're eleven, buying your school supplies and gazing in fascination all around you. This is a new world, one you've been privileged to enter. Stern, no-nonsense Professor McGonagall shepherds your parents through the bar they can't see and then a brick wall turns into an archway and you can't help but think of The Lion, the Witch, and the Wardrobe. Your older sister follows, scuffing her shoes and trying not to look interested. You still don't understand why she didn't get a letter too; you've always done strange things, and Sev has explained that's because you're a witch—but Tuney doesn't seem ordinary, or 'Muggle' at all to you. Your parents do, just the tiniest bit, and this makes you feel guilty.
You've never been particularly greedy, and you long to share your magic adventure with Petunia. But you can't help your amazement—this is Diagon Alley, this is magic, and it's yours. You can't believe this is really happening.
Your parents, wide-eyed, exchange money for fat gold coins and silver pieces and little bits of bronze like particularly expensive pennies, and then they buy you a cauldron, smelly potions ingredients, and a magic wand. A magic wand!
You're thrilled with Mister Ollivander, even though he looks down his nose at you and jumps when Professor McGonagall follows you into the shop and looks over her glasses at him ominously. Tuney kicks stones outside, and you wonder if they're magic stones, or if this new world has rocks just like anywhere else.
You wave a few wands about, and just when you're getting into the spirit of the thing, and you've managed to avoid breaking anything else that looks too valuable (your first few tries were shockingly destructive), Mister Ollivander hands you another one, and you know, just like that. Your lips form an 'Oh!' of surprise and wonder, because this feels right. You wave it gently, and beautiful green sparks shoot out. They look like flowery fireworks to your inexperienced eyes.
"Yes, willow, ten and a quarter inches, swishy. Nice wand for charm work," says Mister Ollivander, smiling indulgently.
"Thanks so much," you say, beaming.
You leave the shop, and Professor McGonagall takes you and your family to the bookshop. Your eyes open wide, because already you love to read, and you're picturing Sev's face if he could see these—you wish he could have come, but his mother is taking him next week, when she has a day off from her work at the hospital, where she does some sort of reception or cleaning work, you're not exactly sure which.
At some point, while you're looking for Transfiguration for Beginners (even the names of the books are fascinating), you get separated from your family and Professor McGonagall. You aren't too upset, at first, and you're quite determined to find the book—after all, you aren't supposed to wander off by yourself normally, but surely this is different. Already you're beginning to feel proprietary about magic, like it was invented just for you.
The boy is thumbing through some volumes set higher than you can reach. His hair is shoulder-length, like Sev's, but blonde and much better groomed. It gleams even in the store's feeble light, and this, together with the boy's sweeping black robes, fascinates you. You stare at the hair for a moment, wondering how it can really be that shiny.
Eventually, the boy notices your fixed regard, and turns around. You see that he's about sixteen, which seems ancient to you—almost a grown-up. You smile up at him hopefully.
"What do you want?" he drawls disdainfully.
You're startled by his tone, but decide that perhaps that's just how he speaks, and he can't help it. You keep smiling. "I was wondering if you could help me," you say, trying to sound as posh and grown-up as possible. "I'm looking for Transfiguration for Beginners."
The boy looks bored, but nonchalantly reaches down and grabs a book from one of the lower shelves. "Here," he says, throwing it toward you.
Luckily, your reflexes are good, and you catch it before it hits your jaw. "Thanks," you say politely.
"Say, you must be a first year," the boy says, giving you a more detailed once-over. "What's your surname?"
"Evans, Lily Evans," you say quickly, pleased he seems interested.
"Evans? I don't know any Evans. Are you pureblood?" he asks.
You frown, because that is one thing you don't remember Sev mentioning. "I'm sorry," you say, still polite, "I don't know what you mean."
The boy recoils, looking horrified. "Filthy little Mudblood!" he yells at you.
You flinch, not knowing what the word means but aware it must be an insult. You hug your book to your chest, and sway uncertainly.
"Well get out of here!" shrieks the boy angrily. "I should never have helped you, you're an abomination against our society." And he strides away in disgust, forgetting whichever book he'd wanted to bring with him.
You stand, watching him go and clinging to your book for protection. You still don't know exactly what he said to you—and you plan to ask Sev at the earliest opportunity—but you can't help feeling lost and forlorn as you walk back toward your parents.
The blonde boy has taken away your pleasure in being here, in Diagon Alley, in a store filled with spellbooks, the proud owner of an actual wand…You heave a melancholy sigh, then paste another excited smile on your lips for your parents and Professor McGonagall (you already know Tuney doesn't want smiles).
You're still a witch, but some of the magic is gone.