Later on, she will feel more favorably toward the message than she did at first.
The sleeper effect says that when people are exposed to a persuasive message followed by a discounting cue (like a less-credible high school dropout) they will initially feel less persuaded by the message but over time will become more persuaded. Even though it was a good idea, Juanita discounted the message because a dropout came up with the idea. Over time, she realized that it was a good idea no matter who proposed it.