With body positivity, baby!

Wait, does she have a crush on you? You only met yesterday, and you've only been talking to her privately for about an hour and a half. Then again, I didn't take long for you to kiss her sister. Is she jealous of her? Nah, she's been fairly casual about it. Is she jealous of me? No, that doesn't make sense on any level. It's just a weird thing to ask. With how nervous she was you would almost think that she actually hate her ow-... Oh, this is what it's all about. Alright. You've never done the "body pep talk" before, but here goes...

"Listen Olivia..." you start "if I said you have a beautiful body, w-" she interrupts.
"I wouldn't hold it against you." she finishes your sentence with a self-satisfied grin. She then reads your serious expression before timidly apologizing.
Fucking smartass...
"No... if I told you that your body is beautiful, would you believe me?"
The room falls silent. Olivia avoids all eye contact, like the Mona Lisa on opposite day. You'll take the awkward silence as a "no". Also the crying. The crying validates your assessment.
Oh wait... shit, she's crying. That's not good. What to do? You guess you'll have to compliment the ever-loving crap out of her body.
"Ollie, your body is stunning." you say in the most warm and comfortable voice you can manage.
"No it isn't..." she trails off: "My body isn't as toned as Sis', and my tits aren't as big as yours, and I am a bit chubby, and I have this weird mark on my-" you interrupt, while channeling your inner Oprah.
"Hey, cut that shit out! First of all, be glad your boobs aren't this size. Do you have any idea of how sore my breasts get? Or my back for that matter? Running is annoying, bras are a nightmare to find, and I can only go around braless when I'm home, but you have the perfect size for perkiness. Second of all, don't compare physical beauty with athleticism. So what you don't have a six-pack? Your tummy is fucking adorable. Your ginger hair, your amazing green eyes, your freckled face, your cute and mushy stature oozes charm and personality. And your charm and personality? Absolutely fantastic, and that is the aspect of yourself that you should be focusing on, not how a couple of your thousands of different chromosomes assigned at birth might differ from shallow people's consensus of beauty. Think about it this way: your sister might have what some very stupid people would call a more "traditionally attractive" body, but think of how much time and effort she has to put into it. You've managed to be absolutely gorgeous, while focusing on being a smart, witty, and sensitive soul. You're beautiful, girl, get over yourself!"
"B-but I-"
"This isn't up for debate, Olivia. You're cute as fuck and that's final."

You see her cheeks slowly matching the colour of her hair.
"Uhm..." she stammers: "Actually, you only have 46 different chromosomes in your body. You're thinking of genes, which are the sequences of DNA and RNA that makes up the genetic code that can be translated into protein, which happens by gene expression, where DNA kind of transcribes to mRNA, and then-"
"You lost me at RNA." you interrupt: "But it's pretty cute when you get all nerdy about... biology?"
"Microbiology."
"Right, microbiology, of course."

Another silence, and a bit more blushing from Olivia.

"Hey, Astrid?"
"Yeah?"
"T-thanks."
"No problem, Ollie... you don't mind me calling you that, do you?"
"O-of course not."

Another silence.

"Wait, you didn't do anything weird to my body while I was passed out, right?" she mockingly asks with a goofy smile.
"Okay, that's it! I am never going to be nice to you ever again."
You both laugh a bit.