Having the knowledge of a life skill always comes in handy as it helps a person in the most unexpected moment. A 12-year-old girl from McKinney, Texas can vouch for it now as she was able to save her little sister, who was struggling for her life after choking on a piece of candy, using a skill she had learned in a training session just hours ago, as per CBS News. The big sister had enrolled in a babysitting training class, sponsored by the McKinney Fire Department with help from Baylor Scott and White nurses, and what she learned there helped her divert a tragic incident that could have changed her life…