1. I recommend you read the many threads on this board regarding tips for beginners, and before you get started watch (and re-watch) all the "Surf Simply" videos on youtube. There's tons of guides on the web, read as many as you can find.
2. As a beginner, you generally want to start on a long board with lots of width and volume. Usually, we would recommend a longboard 9 feet or longer. At your size, you can probably get away with something in the 8 foot range or maybe even 7'8" or something. Just make sure you don't get a shortboard - they are hard to learn on.
3. Never surfed in SC, but I am sure there are sharks there. There are sharks in the vast majority of good surf spots. In most of these places, shark attacks are extremely rare. It is a risk all surfers take, but a fairly small one and we all take far greater risks every day. You are far more likely to die / be injured in a car accident, etc. There are some places (Northern Cal and New Smyrna Beach, FL, to give two examples) that are more "sharky" and have higher rates of attacks than other places. I'm sure someone can tell you where SC falls on that spectrum. My advice is don't surf alone (important for other safety issues besides sharks) and try to avoid surfing sharkier locations if you aren't comfortable doing so. But not a reason to not surf.