Course teaches baby sitters to be responsible By Katie Bolinger, 15, Lauren Bruns, 14, Britany Lewis, 15I n the United States, baby-sitting is a major money-making enterprise for teenagers. According to a 2005 survey by Junior Achievement, more than 11 percent of those ages 13 to 18 who work during the summer are employed as baby sitters. For teens ages 13 and 14, baby- sitting is the biggest employer, with more than 25 percent engaged in such work. Baby-sitting is one of the few jobs open to younge