At the age of four, Stefani began gymnastics at Desert Lights where she moved through the Hot Shots and Pre-team easily. She then started competing level 5 in 2004. She competed in a few invitationals in the spring. At the Spring State Championships, she finished seventh in the all-around as well as third on vault and second on balance beam. She improved her all-around score by three points for the fall season. She won the all-around and floor exercise titles at the School Days Invitational and Halloween Meet. She finished second in the all-around at the PGA Invitational. She then won balance beam, floor exercise and the all-around titles at the Rock-n-Roll Classic. Her final level five meet was the Arizona State Championships, where she won balance beam, floor exercise and the all-around.

As a level 6 gymnast in 2005, she began her season at the Fiesta Bowl, where she won the floor exercise title. She finished third in the all-around at the Phoenix Open Gymnastics Challenge. She then won the all-around title and finished second on vault, uneven bars and floor exercise at the Winter Classic. At the Spring State Championships, Stefani finished second in the all-around and first on uneven bars and balance beam. Stefani also competed as a level six in the fall season. She took home the all-around titles at the School Days Invitational and PGA Invitational. At the Level 6 State, she was crowned the all-around champion. She also finished third on vault and uneven bars as well as second on floor exercise.

Immediately after her 2005 season, Stefani moved up to level 7. She finished third in the all-around and second on balance beam and floor exercise at the Winter Sun Invitational. She then placed first on uneven bars at the Hard Rock Invitational. At the Winter Classic, she won every event except for balance beam. Stefani won another all-around title at the Buckeye Classic. Her final competition was at the State Championships. She won vault and floor exercise and finished second in the all-around. That same year, Stefani made the National TOPs “B” team. She also was awarded the Arizona's Compulsory Gymnast of the Year.

Stefani moved up to level eight in 2007. She finished second in the all-around at the Winter Sun Invitational. There, she won every event except for balance beam. At the Crystal Cup, she finished fourth in the all-around and first on uneven bars. Stefani won the all-around titles at the Tucson Invitational and Buckeye Classic. At the State Championships, she finished an impressive fourth in the all-around and took home three medals on vault, uneven bars and floor exercise. There, she also qualified to Level 8 Regionals. At the Level 8 Regional Championships, she tied for third in the all-around and balance beam. She also tied for first on floor exercise. After the level eight season, Stefani qualified to hopes pre-elite and competed at the US Challenge in Battle Creek, Michigan. At the end of 2007 year, Stefani made the National TOPs “A” Team. She also was voted the Most Improved Level 7 gymnast.

After Stefani's successful 2007 season, she moved up to level nine and continued to compete as a pre-elite in 2008. Stefani began her 2008 season at Winter Sun Invitational, where she finished second in the all-around as well as first on vault and floor exercise. At the Hard Rock Invitational, she placed 10th in the all-around and first on vault. Stefani then won the all-around, vault and floor exercise titles at the Fiesta Bowl. At the Level 9 State Championships, Stefani grabbed the all-around title as well as first on vault, uneven bars and balance beam. She qualified to Level 9 Regionals, where she finished 20th in the all-around. In May, Stefani competed at the US Challenge and finished sixth overall in the Hopes (12 Years Old) division. At the end of 2008 season, Stefani was awarded the TOPs Gymnast of the Year.

In 2009, Stefani began her season at the Winter sun Invitational, where she finished third in the all-around, third on uneven bars and first on vault. She then placed fifth in the all-around anf first on vault at the San Diego Classic. Stefani won the all-around, vault and uneven bars titles at the Fiesta Bowl. Right before the Level 10 State Championships, Stefani tored the meniscus in her right knee. Stefani had a successful surgery and bounced back right before the regional Elite Qualifier in Arizona, where she finished second in the all-around. At the US Challenge in Des Moines, Iowa, Stefani won the all-around, vault and balance beam titles. She also took home two more medals on uneven bars and floor exercise.

Stefani was injured in the beginning of 2010 season but returned at the Level 10 State, where she won both uneven bars and balance beam titles. In June, Stefani placed eighth in the all-around and third on vault at the Arizona National Elite Qualifier. Stefani then traveled to Florida for another qualifier. There, she qualified to junior international elite as well as to the VISA Championships after placing sixth overall. In July, Stefani competed at both Texas National Elite Qualifier and US Covergirl Classic in Chicago, IL. At the VISA Championships in Hartford, CT, Stefani finished 35th overall and 16th on balance beam.

In 2011, Stefani placed second in the all-around at the Lady Luck Invitational and eighth in the all-around at the Fiesta Bowl Invitational. At the Gliders Elite Qualifier, Stefani re-qualified to junior international elite after placing second overall. At the WOGA Classic, she won the all-around title and qualified for the Nastia Liukin Supergirl Cup. At the Supergirl Cup in Florida, she placed tenth on balance beam. Stefani placed sixth on vault and floor exercise at the American Classic and concluded her 2011 season at the US Covergirl Classic.

Currently, Stefani is preparing for the upcoming 2012 season at Desert Lights in Chandler, Arizona under coaches Lisa Spini, Neela Nelson, Bruce McGehee, Bob Peterson and Chris George. Stefani's long term goals are to compete internationally and to receive a college scholarship.

Stefani Marie Catour was born on July 28, 1996 in Chandler, Arizona to Randy and Beth. She has an older brother, Brandon and a younger sister, Tara. Currently, Stefani is in 10th grade at Horizon Honors High School.