Actually, getting your head cut off was probably pretty high up there with the worst that could happen, and he'd survived that, right? So....
"Well, if there's magic here, it means that magic can help us. So I can just learn this shit and use it and... Everything will be fine and good will win and it'll just be another big adventure to tell Henry about." After she'd watched every happy, clappy, singing, fluffy movie that there ever was in order to cleanse her brain.
She'd survived the foster system, she'd survived jail, she'd survived losing Henry and Neal and all the other stuff. She could survive this. She had magic now, she knew it now, she could do this. "Right, okay, no freaking, we'll be fine. No freaking. Let's go find a tailor before I start freaking again."
Because she was sure this new found burst of 'magic is good, I have magic' wouldn't last all the way through the night.