I'm Supergirl in a Weird Crossover!? (DC x Twilight)

"I've been Isekai'd and reborn as Supergirl! Wait!? Where are all the other super heroes?...Are those vampires Sparkling...Dammit! I'm in a Crossover!" (-A DC/Twilight/TBA crossover story) Reincarnated as Supergirl in a world where the other heroes don't exist yet. Self Insert.