Fittingly, it's almost the end of the world again when Homura finally finds its version of Madoka.
Although, actually, she's already met the counterpart. Several times. She just took a long, long time to realize she recognized her, and now she almost wishes she hadn't.
It takes all the self-control Cheren was brought up with for fifteen years and all the experience Homura was jaded with over a single endless month, all their combined fatalism and strength to fight for what they want, for Homura to accept it.
Because it means she's already failed, she was already too late when this world started.