I have heard phrases similar to that before. You asked her if she was a quilter and she said no, she quilts 'at it'. She was being very modest...she does not consider herself a quilter for whatever reason...maybe she does not feel she does a good job at it, maybe she does not spend that much time at it, maybe she is just learning, maybe she is implying that she does not put herself in the league of you women who are so very talented.
I have used that phrase before...for instance...when I know I don't do a good job at something or I am just kind of trying things out.