Alps from Kiken na Mori Onigokko, an anime by studio Magin Label.
It's a derivative work of Alps and the Dangerous Forest/アルプスと危険な森, a game by developer X-Rabbit
Now in Illustrious. Might update when episode 2 is out. I still don't know what that thing in her collar is supposed to be.
Description
keywords: alpsogkkoilus, grey hair, long hair, one side up, hair ribbon, hairclip, red eyes, orange eyes, multicolored eyes, large breasts, jacket, high collar, hood down, shirt, shirt bow, pleated skirt, thighhighs, blue mary janes,