She is one of those types who makes me feel uncomfortable anyway as she is very loud and says whatever is on her mind. My issue is she keeps telling me that my job as a daycare supervisor and out of school activity leader is beneath me.

She openly says that at 29, I am a bit old to be doing these jobs and should be doing something like becoming a health care assistant. It upsets me as I then worry everyone thinks the same and really, all she should be concerned about is how her son is looked after (which is very well and he loves coming). How do i politely tell her to back off?