i remember Jun talking about this somewhere. Jun revealed the truth, her birthday is actually January 11th, not Feb. 11th. due to a registration mishap by her mother when she was born.
the Kamei family went on a road trip to Niigata. Rina was the driver for a couple of hours. Kamei mama and Eri made riceballs for her sister. they made a stop a couple of times, and Rina had ice cream 3 times. http://ameblo.jp/kamearu/entry-10997856729.html