Avdija was born Jan. 3, 2001 in Beit Zera, Israel. His father, Zufer, was a professional basketball player. His mother, Sharon, was also a basketball player, plus a track and field athlete. Avdija holds dual citizenship between Israel and Sebia -- his father is a Serbian citizen. Avdija originally played soccer, but focused on basketball in the fourth grade. From 2017 to 2019, Avdija led the Maccabi Tel Aviv hoops squad to three consecutive Israeli youth state championships. In August 2018 in Belgrade, he participated in Basketball Without Borders Europe, where he earned camp MVP honors. After three seasons on Israel's junior national team, Avdija joined the senior team in February of 2019. When Avdija turned 18, he received a deferment from mandatory military service in Israel due to his basketball career. However, he was drafted into a short service program in April of 2020 due to the COVID-19 pandemic suspending basketball.