Is this repairable/worth it?
Junk it. Get a shell and swap over everything would probably be your best bet. Either that or buy a new 7. The quotes for body repair in here are a tad low, probably around $1500 to repair, I'm talking a cut and weld job though, no 2" thick bondo mexican repair. I would also inspect a bit further on the whole structural damage thing, remove interior pieces, tailights, etc. By the way, yes it is your fault even if she was speeding or not, you obviously misjudged something and continued anyways. Sorry about the car.
ALSO if this was a FD EVERYONE would say t repair it but since its a fc everyone else things you might as well get another shell. F THAT!