Dare I say she is from the Harry Potter series? She looks distinctly like a pink haired Hermione Granger, but I do not see a Hogwarts’ badge or scarf anywhere. And besides, when did Hermione ever change her hair color?
Feel free to post your thoughts in the comments below! Thanks again to Hannah!
EDIT: Thanks to anon for commenting this is Louise Françoise le Blanc de la Vallière from Zero no Tsukaima (The Familiar of Zero)!