LAWRENCEVILLE — A woman charged with killing four of her young children and her husband smiled and flashed a double thumbs up to news cameras during her first court appearance Friday in metro Atlanta before telling a judge she doesn't want an attorney.Also, an immigration official said the woman, who is from Mexico, entered the U.S. illegally.Isabel Martinez, 33, appeared before Gwinnett County Magistrate Court Judge Michael Thorpe a day after police said she stabbed the five to death and seriously injured another child at her home. The surviving 9-year-old girl remained hospitalized with serious injuries.Before the hearing began, Martinez sat with other inmates and posed for cameras — smiling, giving the thumbs up, putting her hands in a prayer position and spreading her arms out wide.As Thorpe listed the charges — five counts of malice murder, five counts of murder and six counts of aggravated assault — Martinez smiled, shook her head "no" and wagged her finger at him."Ma'am, I'm going to caution you to cut out the display for the cameras," he said. "It's really not a good idea, probably not to your benefit."When Thorpe said she had a right to an attorney, she replied through a Spanish-language interpreter that she doesn't want one.