As a child, Iwao became interested in pi. She was inspired by Japanese mathematicians, including Yasumasa Kanada. She studied computer science at the University of Tsukuba. Daisuke Takahashi taught her there. She won the Dean's Award for Excellence in 2008, before starting graduate studies in computing. Her master's dissertation was about high performance computer systems. After graduating, Iwao worked as a software engineer for Panasonic, GREE and Red Hat.