Not every job is for every person. You have to be able to do the job effectively. You can't just ~hope~ that the kids allow you to do the job. You have to have the right disposition and skils, etc to do a job.
Not really about size or gender. More about disposition.
If you work w/ teenagers, you have to be very assertive. This woman was not. Maybe she was at one time or maybe she never was. I know some old women meaner than a brood of vipers and you woud not wanna cros them! OL