At age ten Sims started ballet classes at the Long Island Institute of Music in Queens on Parsons Blvd., under the tutelage of Helene Vinson.
Those studies were supplemented with summer training at the ABT school under Michael Maule, Patricia Wilde, and Madame Swoboda; and at the New Dance Group Studio with Peter Saul and Margaret Craske.
After graduating high school, Sims was accepted into the trainee program at Harkness House under David Howard and Maria Vegh.
She had also trained with Helen Greenford and Elizabeth Carrol in ballet; Luigi in jazz and Teresita La Tana in Spanish dance.
German dance critic Wilfried Hofmann began to refer to Sims as the ‘Judith Jamison of ballet'.
She played both the "cool" second violin in Balanchine's Concerto Barocco, and the world-weary lady in pursuit of a bored gentleman in Cata's Ragtime.
In May 1978, Dustin Hoffman and Alfonso Cata presented her in the highly successful Ballet on Broadway at the Beacon Theatre.
In a 2014 interview, Misty Copeland said that Sims was part of the “corps de ballet,” or a member of the larger dance troupe, first.
[18] "I haven’t been doing the 'white' acts of Swan Lake or Giselle, but there is a bit of slush in the 'Snow' section of Peter Tchaikovsky's The Nutcracker Suite" says Sims.