According to the narrative in Ezekiel 23 it is said Israel began her prostitution in Egypt whilst still a youth. She is symbolized as two sisters, Oholah and Oholibah, which seems to refer to Jerusalem and Samaria:
Ezekiel 23:1-3 NIV
The word of the Lord came to me: 2 “Son of man, there were two women, daughters of the same mother. 3 They became prostitutes in Egypt, engaging in prostitution from their youth. In that land their breasts were fondled and their virgin bosoms caressed. 4 The older was named Oholah, and her sister was Oholibah. They were mine and gave birth to sons and daughters. Oholah is Samaria, and Oholibah is Jerusalem.
Ezekiel 23:19 NIV
9 Yet she became more and more promiscuous as she recalled the days of her youth, when she was a prostitute in Egypt.
Ezekiel 23:27 NIV
27 So I will put a stop to the lewdness and prostitution you began in Egypt. You will not look on these things with longing or remember Egypt anymore.
But according to the book of Exodus when Israel was a youth she was serving in Egypt as a slave.
What were the acts of prostitution did she commit?