Question about self defense

So I am 19 so I can not get my permit for another 2 years but I plan on getting it and carrying. Recently there was a post on r/AskReddit asking for stories about people acting in self defense. A lot of the replies talk about people being sentenced for Involuntary Manslaughter because of lack of CCTV or witnesses. Now I am not sure if this is the correct way to articulate this but when you shoot someone (in self defense), is it assumed that it was manslaughter/ murder and you have to prove it was self defense or the other way around?I don’t exactly know what answer I am looking for but the whole idea of being wrongly sentenced when acting in self defense makes me a little uneasy so maybe some of you can provide some insight on this.Edit: I do not plan on carrying before I turn 21 since that would be illegal I am just a teenager looking for some answers before I turn 21. The main reason I ask is because I do want to learn the legalities and do training before I turn 21 to make the transition easier.Also I am in Miami Dade County, FL. But I don’t know how relevant that is since I might be moving after I finish school. via /r/CCW https://ift.tt/2Jh7r4z