I have a few old friends from the days when I had a whizzy job who thought I was bonkers when I took the job I now have (lower pay, part-time, less stress, more flexible).
If you have explained to her that the job may not be the most exciting one but it suits you then I think hwen she suggests it again then I would turn it into a question.
"why do you keep advising me about changing jobs when I have told you I'm happy with this one. Do you have a problme with my job?"
A question to her will flush out what her real issue is (if she has one) and will change the cycle of her telling you and not listening to the answer.