Going one better than her recent series of national records in the pole vault, Katerina Stefanidi, 15, yesterday set a new world youth indoor record with a 4.37-meter jump at an international meeting in the Greek capital, ‘Athens 2005.’ On her way to eclipsing the world’s previous best, a 4.31-meter performance held by German Monica Getz since May, 9, 1998, Stefanidi also broke two national records. In post-competition remarks, the confident young athlete said she was expecting the result. A few days earlier, competing at the 12th Indoor Balkan Games, Stefanidi had set national juniors’ and youth records at 4.25 meters.