What is a good way to tell someone older than you to stop talking?

im a christian and i am trying my best to abstain from doing things we arent supposed to do, and that involves gossiping but sometimes i will all up someone older than me and all of a sudden she'll just start dishing everybody's dirt, as if im a dumpster or something. i don't want to be rude, and i don't want to be one of those self righteous people who quotes scripture all day. how do i politely (and realistically) get her to realize that what she is doing is wrong?