Answer by taking a quote from the following article:

Agnetha Ase Faltskog (Swedish pronunciation: [aNG2ne:ta 2feltsku:g], born 5 April 1950) is a Swedish musician, singer, songwriter, actress, and author. She achieved success in Sweden after the release of her debut album Agnetha Faltskog in 1968, and reached international stardom as a member of the pop group ABBA, which has sold over 380 million albums and singles worldwide, making them one of the best-selling music artists in history. After the break-up of ABBA, Faltskog found some success as a solo artist in the 1980s, though also became more solitary, avoiding outside publicity and settling  on the Stockholm County island of Ekero.

Faltskog worked as a telephonist for a car firm while performing with a local dance band, headed by Bernt Enghardt. The band soon became so popular that she had to make a choice between her job and her musical career. She continued singing with the Bernt Enghardt band for two years. During that time, Faltskog broke up with her boyfriend Bjorn Lilja; this event inspired her to write a song, "Jag var sa kar" ("I Was So in Love"), that soon brought her to media prominence. At that time, Karl Gerhard Lundkvist, a relative of one of the band's members, retired from his successful rock and roll career and began working as a record producer at Cupol Records. Enghardt sent him a demo recording of the band, but Lundkvist only showed interest in Faltskog and her song. She was worried because he was not interested in the band and they were not to be included on the record. However, she decided to accept the offer, and signed a recording contract with Cupol Records. Her self-penned debut single "Jag var sa kar" was released through Cupol Records in 1967, and topped the Swedish Chart on 28 January 1968 and sold more than 80,000 copies. She also submitted the song "Forsonade" ("Reconciled") to Melodifestivalen, the Swedish preliminary for the Eurovision Song Contest, but it was not selected for the final. Faltskog developed a career as one of Sweden's most popular pop music artists, participating in a television special about pilots in 1968. The same year, she released the single "Zigenarvan" ("Gypsy Friend") about a young girl attending a Gypsy wedding and falling in love with the bride's brother. Its release coincided with a heated debate about Gypsies in the Swedish media, and Faltskog was accused of deliberately trying to make money out of the situation by writing the song. Faltskog's success continued throughout the late 1960s. She met German songwriter/producer Dieter Zimmerman, to whom she became engaged. Her albums thus reached the German charts, and Zimmerman promised her she would achieve great success in Germany. However, when she went there and met with record producers, the venture was not productive; Faltskog refused to meet the demands of the producers, describing their chosen material as "horrible". She soon ended her engagement to Zimmerman and returned to Sweden. In 1970, she released "Om tarar vore guld" ("If Tears Were Gold"). A Danish composer claimed that she used 22 bars from his composition "Tema" ("Theme"), even though it was written in the 1950s and had never been recorded. The case dragged on until 1977, when a settlement was reached and Faltskog paid the Danish musician SEK5,000. In 1972, Faltskog portrayed Mary Magdalene in the Swedish production of the international hit musical Jesus Christ Superstar. CANNOTANSWER

How did her career begin in 1966?

Faltskog worked as a telephonist for a car firm while performing with a local dance band, headed by Bernt Enghardt.