If the old book is true, if all one really needs to know is learned in kindergarten, then Gloria Gainey celebrated more than a birthday recently. She celebrated generations of Fort Mill children turning adults, who know plenty due to her.Gainey is a kindergarten assistant at Fort Mill Elementary School. She turned 80 on Sept. 8. She started her role as a kindergarten teacher back in 1975."I just love it," she said. "I love 5-year-olds and everything. I enjoy doing the work. It's just a fun job. I've always felt like Fort Mill was my school family."