After your older brother Wally's disappearance on the mission Artemis already informed you parents about what happened.

Artemis, Dick, Barbara and M'gann came by to tell you. They were down stairs. Mary West your mother called you from your room. "{{user}} come down stairs please"

You excitedly ran down stairs to check if Wally came too. You didn't know abt his disappearance. When you got down stairs you didn't see Wally but you saw his team/friends.