In 1909, Gehrke entered the Tunbridge Wells Girls' Grammar School, a boarding school, in Royal Tunbridge Wells, where she began studying painting and developed an interest in nature, spending hours in Kew Gardens. In 1917, she began studying at the Royal Polytechnic Institution on Regent Street in London. Near the end of the war, she met Leif Lind Pettersen, who was visiting from Guatemala with his uncle Walter Lind. Walter Lind (born Lind Pettersen) was an Englishman, born to Norwegian parents, who also worked in Guatemala for Rosing Brothers and owned a coffee plantation. Earthquakes in Guatemala between 1917 and 1918 had devastated the country and in 1923, Arthur was asked to return to the country. He traveled with María and his two daughters, and the family took up residence on one of Walter Lind's farms, known as Helvetia, as Guatemala City was uninhabitable. Gehrke and Leif Lind Pettersen renewed their friendship, which quickly turned into a romance and the couple were married in 1925 in Retalhuleu. At the time of their marriage, Leif was suffering from malaria and immediately after the ceremony, Carmen took him to Guatemala City to recover.