Two Sides of the Same (Twisted) Coin

I'm sitting at my desk, doing homework, when the mirror shard hanging on a cord around my neck pulses. I get out of my seat, breathe a shaky breath, close my eyes, and stand in front of my mirror. I open my eyes and see her.
"What do you want?" I demand. She smirks.
"What, no welcome? No hello? No 'Hey, best friend, don't you want to go on a mall date?" she asks, leaning forward and resting her elbows on her side of the mirror ledge.
"No," I say, my voice shaky.
"No?" she asks. "No? All I do for you, and no?" She gets up, uncrossing her legs and getting to her feet. She places her hands on the mirror, the piece of glass between us. "Is that how you're going to be?"
I don't respond, just cross my arms over my chest and look at the floor.
"Come here, Kadelyn," Her voice is smooth, commanding, and utterly confident. Everything that I'm not.
I shake my head.
"I said, come here," she repeats, forcefully.
I shake my head more vigorously. "No."
She gives me the death glare. "Give me your hand or so help me-"
"What?" I interrupt her, surprised by my own boldness. "You'll what? You know that you can't do anything in the Real World or the Mirror World unless I let you. Which I'm not. So-so stop asking." My voice isn't as steady as I would've liked.
Her eyes glitter dangerously, and she sits back down, tipping her chair back on two legs and resting her legs on the mirror sill, ankles crossed and tail flicking back and forth on the floor, whether in anger or interest, I can't tell.
"But I'm so bored!" her tone is now whiny, and the look on her face makes me almost pity her. Almost. I wonder how she does that when I have such a hard time expressing any feeling? Her attitude has done a complete 360. "I haven't done anything in forever. How would you feel if you were stuck in a boring place, with nothing to do, for months on end, and only getting a couple hours of activity every couple months, or whenever another person, another unsympathetic person, decided to let you? How the hell is that fair?"
I hesitate, my resolve wavering. Well, maybe, I think. But... "Whenever I let you out, you always screw up everything. Why in the world would I want to do that?"
She bolts upright in half a second, on her feet, chair on the floor, eyes flashing with anger, wings out, tail flickering definitely angrily, and starts yelling: "I do not screw everything up every time. It's not my fault that you don't have the guts to do anything out of the norm, anything that anyone will pay attention to you for, it's not my fault that you can't do anything other than what you're told to, it's not my fault that you couldn't keep things up with that boy I set you up with, it's not my fault, it's not my fault, it's not my fault. And those rare few incidents where I messed up? Don't tell me that you've never messed up before, Miss Perfect."
For a long minute, I don't respond. I've never gotten this far in our arguments. I've always given in before now. It feels strangely exhilarating, but I also feel a little guilty at the same time. I would probably act the same way if I was treated the way she is. I mean, I would, of course, obviously.
"I'm sorry, but I like my life how it is. I don't want you meddling in it. I'm sorry that that means that you have to stay there, bored, but it's my life, and I want control of it. I don't want to share the wheel, or even have a backseat driver, I want to be the only one in the car. So, I'm sorry, but no. Never again. I'm sorry, Kade."
She steps back, betrayal mixed with the saddest look I've ever seen on her face. As she starts to disappear, I close my eyes and add one last thing.
"And for the record, I'm not best friends with my alter ego."
When I open my eyes, all I see is my own reflection.