How old was Serena Williams when they won their first Grand Slam singles title?

Serena Jameka Williams is an American professional tennis player. She was ranked as the world No. 1 in women's singles by the Women's Tennis Association (WTA) for 319 weeks, and finished as the year-end No. 1 five times. Williams won 73 WTA Tour–level singles titles, including 23 major women's singles titles—the most in the Open Era, and the second-most of all time. She is the only player to accomplish a Career Golden Slam in both singles and doubles, and the only player to have simultaneously held Olympic gold and all four major titles in both singles and doubles.