Whenever you act or speak publicly you share a part of yourself with the audience. You may hide behind a persona, or even a character, but at the center is the truth of you. This is not escapable.
How much you reveal of yourself varies. Really, it all depends on how much of you is poured into the performance or presentation. In an Original Oratory, specifically, you can keep your exposure to a minimum and let yourself come across through the mannerisms, gestures, and tone you project to the audience. Or, you can be bold and divulge a personal secret. Telling a small, hopefully captivated audience about your battle with cancer as a hook/example for a speech on a particular form of cancer research can be emotional and connect those listening to the topic.
But how much is too much? Just as a magician never reveals their secret, you do not want to expose all you are. There are numerous reasons for this:
Too much detail can lead to awkwardness. Unless you personally know an individual, having knowledge of extremely personal information leaves you wondering how you should react. Intimacy to an extent is good, but too much and things get weird.
Your story might be riveting to you and those who know you, but to an outsider you are just a nameless face. We want to care and be sympathetic as people. However, everyone has their own trials and hardships. We also get bored with a story we probably have heard a variant of before. To be blunt, too much detail gets boring. Fast. Keep it short and direct
People love a story of struggle and triumph. People love to sympathize with a sorrowful tale as well. Thus, if you choose to tell a personal story, be warned that if you go too far you will be seen as merely seeking a sympathy vote. Don't be that person.
A fact to keep in mind is that Original Oratory is basically a research paper. Your personal account is wonderful to include, but you should really try to keep to credited sources. Get back to facts and science and learn to mingle the emotional in there so it is more for impact and less to woo your audience.
