It's also got yellow eyes and Marisa's hair length. I'd say it's Marisa in Reimu cosplay, but I'm not gonna just throw the tags there hastily.
It sure doesn't seem to be Reimu though. I'm going to tag it as Marisa because like you said, it's the right hair/eye color and hair length - no one else has that exact combination, other than in maybe the odd Yukari picture.
But of course I ask anyone to correct my tags if there's a better idea, which there may be.
Pixiv title is "Reimu" and the tags are "Hakurei Reimu", "Touhou", "analog" (meaning traditional) and "watercolor". I'm removing the Marisa tag and adding alternate hair length and alternate hair color.
