"Stop waiting. Don't wait."
She was referring to the writing and publication process. So often, we aspiring writers hear the message, "Don't give up." As true as this message is, it has an implicit pessimism to a certain extent. It is telling us to expect the road ahead to be challenging and perhaps even daunting. While this may be true, it is no way to begin a journey!
Rather, "Don't wait" is filled with far more agency. It is not saying you will or will not get published. There is no guarantee in this statement. It simply seems to speak to the one universal truth in writing: you absolutely will never get published if you don't take the steps to do so. In that light, WRITE, REVISE, and FINISH your work. Then worry about publishing.
I don't know, maybe the messages aren't all that different -- or maybe they are. But "don't wait" sure sounds a lot more appealing than "put on your raincoat."