In a persuasive speech, you tell a hypothetical story in your introduction and represent it as actually happening to you. is this appropriate?

This is not an ethical action. One of the main tenets of persuasion is that the speaker is honest about what they are trying to persuade the listener of. When the speaker is misrepresenting their position and the actions that they are presenting, it can lead the listener or viewer to a false conclusion about the veracity of the information.