Rosario Tobar is a U.S. citizen at last. The Kasson woman, known as “Chayo,” moved from Mexico in 1996, and finally took the naturalization Oath of Allegiance this past Sept. 19 during a ceremony in St. Paul. She was among 21 people who officially became American citizens. “I cried,” Tobar said. “I’m so very happy. I fit in here. I am here. Now it’s my country.”“It was one of her dreams come true,” said her husband, Sam Lopez.