Prince George's students returned to their classrooms Monday, a week ahead of most of the other public school systems in the Washington area. The county system, with a projected enrollment of 139,410 and a 2005-06 operating budget of nearly $1.4 billion, is being led by interim schools chief Howard A. Burnett, who has pledged academic continuity in the face of challenges, including the ongoing struggle to raise test scores. Among the changes this year are three new elementary schools, a rebuilt Bladensburg High School, the conversion of the former Samuel Ogle Elementary in Bowie to a middle school and new bus routes for many students. Emily Kendall kisses her son Jordan, 6, after his first day in kindergarten at Whitehall Elementary School. At right, families escort children to class at Suitland Elementary. Below, Suitland teacher Edith Allen is surrounded by parents and students as she checks a list of names and classrooms.Clockwise from left, Dione Smith, 6, left, and her brother Dorrian, 5, wait with their mother for Freda Porter, assistant principal at the new Suitland Elementary School, to tell them which classrooms to go to; elsewhere at the school, Ricky Gibson, right, talks with son Dayvon, 4, about his first day in kindergarten; at Whitehall Elementary, a new school in Bowie, physical education teacher Kelsey McClelland guides students to one of the buses; and Whitehall kindergartner Isabel Montero, 5, yawns while she waits for dismissal.