Describe a situation where you had to make a quick decision.
When working with youth there are going to be unexpected emergencies that you'll need to act fast during. The interviewer wants to know about a time that you had a deal with an emergency while working.
You don't have to have a huge rescue story for the interviewer, as long as you give them an example of a time that you were under pressure and had to make a quick decision. If you don't have an example of one while working with youth, you can also talk about a time with a different emergency from your personal life.
"I was the lead for a group of children that were inside when a fire alarm went off. The other groups were all outside for recess at the time, so I had to lead my students outside to meet the rest of the students. We had no prior knowledge that a drill was going to happen, so it was the first time I had experience getting the students out by myself."