I recently heard Brunonia Barry talk about her very successful first novel, "The Lace Reader," a Mary Higgins Clark sort of adventure/love 
novel set in contemporary Salem, Massachusetts.
Barry, a former scriptwriter with theatre experience who now lives in Salem, quit her job to write a novel -- with her husband's permission, of course. After seven years of research and rewrites, she offered the manuscript to a reading group at a local bookstore. She and her husband then self-published "The Lace Reader" through Flap Jacket Press.
On a whim, she sent a copy off to a friend in Hollywood to promote to the studios. The manuscript landed in the right hands and next thing she knew there was a huge bidding war between publishers. "The Lace Reader" has just been re-released by William Morrow this summer with a major promotion and a $2,000,000 book deal for Barry.
So the moral of the story is this: never give up, success is around the corner. Even for 50 something women wannabee writers.