St. John started playing violin at the age of 2. When she was 5 she already had her first solo performance. At he age of 10 she had her first performance in Lisbon, two and three years later she toured Spain, France, Portugal and Hungary. Due to an Ontario law which permitted it, she was exempted from all school subjects except music. At the age of 14 she entered the Curtis Institute in Philadelphia. After graduating there three years later she wanted to enter the Tchaikovsky Conservatory in Moscow. While she was settling in, many teachers, including hers, were defecting and due to the conservatory's rules she couldn't study with any other teacher so she had a chance to travel around the former Soviet Union and Eastern European countries where she encountered the Roma people and their music. Her further musical academies include Guildhall School, United Kingdom, Mannes College, New York and New England Conservatory in Boston. St. John was victorious at several competitions. In 1997 at a competition organized by the Canada Council for the Arts and an anonymous donor she won a two year use of Lyall Stradivarius dating from 1702. Now she performs on a Salabue Gudagnini from 1779, thanks to Heini & Co. from Toronto and an anonymous donor.