In her junior year, Tatsuno was a steady presence on vault, beam, and floor at every competition. Her shining day was at Brown, when she received a 9.6 on vault, career high 9.8 on beam (1st), and 9.675 (2nd) on floor. She was honored as ECAC Gymnast of the Week after that performance. At ECACs, Tatsuno had the highest vault score and the second highest beam score on the team. Her consistency proved to be a huge benefit for Yale.

Tatsuno competed vault, beam, and floor at every competition in her sophomore year. She consistently was among the top scorers for the team on vault and beam. She scored her season high on vault at the Ivy Classic (9.65), where she placed 5th. On beam she often made it onto the podium, including a win at Southern Connecticut and several 2nd place finishes. Her season high was a 9.725 at home against URI. Tatsuno earned a 9.575 on floor three times, one of which placed 9th at the Ivy Classic.

As a freshman, Tatsuno quickly asserted her presence in the vault and beam line-ups, competing both events at every meet and often earning one of the team's highest scores. She also made a significant contribution on floor, competing in all but three competitions. Her consistent beam work did not go unnoticed. Tatsuno won the event at several meets and earned a berth to the NCAA Regionals, where she scored a 9.7 and placed 14th. At the ECACs, her 9.575 placed fifth.

Tatsuno joined the Bulldogs from West Valley Gymnastics. A consistent Level 10 Region I Championships qualifier, Tatsuno was a contributor to her team's 2003 State championship title. In 2005, she placed 6th in the all-around and 3rd on beam at State and 14th in the all-around at Regionals. Tatsuno graduated from Monta Vista High School.