hi the only thing i can tell is put in her place right away so she know that you not going to let mad mouth you ,sometimes we have to show peolpe that we respect there opinion when we ask them ,but if a person just opens her mouth just to embarrass you in front of others than you have the right to speck up for your self .people like that you have to put them in place with nice words of coure but to the point ,i alway think of what our paster always says use common sence christans so your learning so what we all been there i hopes this help i,m on your side nellie