That would be pretty sweet...
Thor-Girl is Tarene, the Designate, so she's not really a kid. She's supposedly a universal savior. She just developed a hero-worship thing for Thor after he saved her ass from Thanos (Thanos' clone if you believe Starlin's girlish inability to let his baby be beaten by anyone). During "The Reigning," there were somehow two aspects of her, Thor-Girl and the Designate. Loki took Thor-Girl's soul and put it in storage to be used in the Destroyer if he needed it. The other aspect created a gem that could absorb divine energy and weapons that could destroy gods, which she gave to a dude named Desak, making him a god-killer. They remerged through their avatars, creating a hybrid of Desak and the Destroyer, which Thor blew to smithereens with Mjolnir and the Odinpower. As far as I know, she was forgotten when Thor rewrote history so "The Reigning" never happened.
And Thor's choice is, always has been, and always will be Sif. Despite the fact that he's been in love with Jane Foster, married the Enchantress, and had a human fiancee thrust upon him as Jake Olson over the years. And despite the fact that Sif and Beta Ray Bill had a thing during Simonson's run. [teeny-bopper middle-school girl mode]THOR + SIF 4-EVER!!![/teeny-bopper middle-school girl mode]