God, her body is simply perfect. Such a perfectly curvy, and delightful figure, even those arms have the promise of producing some muscle when flexing. The only "flaw" I see with this picture, is that there isn't more versions of it: with a bikini/with or without glasses, in a towel, etc.
Like all of Ando's work, he doesn't create character designs of his own. He just bases all his girls on already established anime/manga/video game characters but gives them new names and uses them in his own stories.
So the answer is yes, this is Rei from Pani Poni Dash, but no, because she has a different name and personality.
There really needs to be a tag for situations like this, since I'm sure anyone looking for images of Rei would be best served by this being tagged as such.