Puck doesn't know the exact moment he fell in love with her.
They'd always exchanged condescending remarks that had a flirtatious hint, never coming too close to revealing any feelings. Puck had always had a 'thing' for her – and he'd really wanted to hook up with her purely because she was hot, and it would be fucking ironic to bed the head of the celibacy club.
But then she started dating no other than his best friend, Finn. They were the head cheerleader and the quarterback – what a fucking perfect cliché. They laughed together, putting on their façade, but in private, Puck just knew that Quinn would be a tease, endlessly taunting Finn – because that was the kind of chick she was. Hot, and a fucking tease.
Puck doesn't miss the glances that Finn wastes on that attention whore Rachel girl, but surprisingly he can't hate Finn for not realising how amazing his girlfriend (he hates that word) is. It goes like this: Finn can be an idiot sometimes (well, most of the time), and he isn't exactly the brightest one around. Maybe it comes with being the quarterback. Finn's his best friend, so he can't hate him. But Puck knows that Quinn deserves better.
Then it happens. She feels fat, so he seeks the opportunity to be nice to her, and hopefully she'll go for him. Puck gets her drunk on wine coolers, and then (he doesn't remember how it happens), he's on top of her, kissing her neck and murmuring to her. She'll swear it didn't mean anything, and so will he (it didn't, right?), and it'll never have happened.
She's pregnant. It's some time around now, that Puck thinks back on it, and starts to feel something. He realises that yes, he has feelings for Quinn, yes, he's had them all along, and yes, he's glad it's his child they're carrying.
Eight months onward, they're standing there, and as Quinn's watching Beth, he can't keep his eyes off her. She locks her eyes with his, and he wonders if she can see the love in them. Because he, Noah Puckerman, is in love with her, Quinn Fabray.
And that's all there is to it.
"Did you love me?"
"Yes. Especially now."