Berezko-Marggrander moved to Germany with her family in 2008 and started training on the federal base in Fellbach with coach Galina Krylenko. She is a member of the club TSV Schmiden. As a junior, she competed at the 2010 Junior International Schmiden where she won silver in all-around behind Russian Daria Svatkovskaya. She won silver in hoop and clubs and bronze in ball final. She won three bronze medals at the 2010 European Junior Championships in the team event and in the ball and hoop finals. She also represented Germany and competed at the 2010 Youth Olympic Games where she won the all-around bronze medal.