Answer
Ter Stegen represented Germany in three different youth teams: the U16, U19, and U21 squads. He made his debut for the U16 team in 2009, and went on to make a total of 12 appearances for the team. He then moved up to the U19 team, where he made 11 appearances, before finally joining the U21 team in 2012, where he made 10 appearances.