Umeh's first big international meet was at the 1989 American Cup in Fairfax, Virginia where she finished fifth. She then competed at the 1990 Commonwealth Games but was originally an alternate. She won a gold medal with the Canadian team. She competed at the American Cup again in 1991 but placed 8th. She went to the 1991 World Artistic Gymnastics Championships in Indianapolis, Indiana, USA. She finished 17th in the all-around. In 1992, Stella started her season at the American Cup in Orlando, Florida, USA and finished 7th. In April, she competed at the 1992 World Artistic Gymnastics Championships in Paris, France. She qualified to Vault and Beam finals but placed 8th and 5th. Later, she qualified to the 1992 Summer Olympics in Barcelona, Spain. She finished 16th in the all-around and 10th with the Canadian team. In 1993, she went to Worlds and placed 15th AA and 8th in the FX final. In 1994, she went to the 1994 Commonwealth Games and won 2 golds and 2 silvers as well as placing 4th and 5th in Floor and Beam finals.