Her mother, Mary Vergoti is a school teacher, her father, Panagiotis, is the commander of the harbor of Rhodes and her younger brother George is a medical doctor.

Starting at sixteen Theodosia studied for five years at the National Conservatory with Aris Garufalis, and graduated with honors, and as she has quoted many times he was "The professor who built her character, and told her never to give up".

Theodosia then continued her studies with Hungarian pianist Laszlo Simon at the Universität der Künste in Berlin and simultaneously received her Postgraduate Degree from the Franz Liszt Academy of Budapest.

Theodosia moved to America, where she completed her master's degree with Russian pianist Oxana Yablonskaya and went on to earn her assistantship at the prestigious University of Hartford-The Hartt School in Connecticut.

In a review of Argerich's and Ntokou's new Beethoven album, Norman Lebrecht from Slipped Disc wrote: and the LA Times mentioned: The BBC Music Magazine has praised Theodosia as: