Nobody here can hand you the perfect answer for you, but there has been a good bit of solid advice already. One of the best was to find a local range/store that gives beginners lessons in gun safety and shooting technique. If they have various guns you can rent, all the better. Get your concealed carry permit. This may require another class, but it won't hurt much and even if you don't intend to carry all the time you have the option.
My specific suggestion for a first gun would be a small revolver such as the
S&W 642 or one of the many "J-Frame" variants. The 38 Special isn't the most powerful out there, but it was very widely used by law enforcement through much of the 1900's. The guns are light, simple, and require less maintenance than semi-autos (pistols). And they also don't require a "break-in" period of 200-500 rounds that many, including myself, feel is needed to assure a semi-auto is running its best.
Whatever sort of gun you get, practice with it until you can keep all of your shots more or less in the middle of a silhouette target at 15-20 feet. It's not that hard to do, but it's not as easy as it looks on television. After that, try to shoot 50 rounds at least every month or two, just to keep your hand in. When you do, use up your 'good' ammunition that has been in the gun and replace with fresh after practice.
At this point you will have done some shooting and learned a good bit. This will be the time to decide if you want another bigger handgun for use as a 'house gun' or a rifle or shotgun. As a person who shoots long guns left handed, I can warn you that many rifles and shotguns eject on the right side with the spent shell flying in front of your face (hopefully) which is annoying at best, and potentially disastrous in a home defense scenario where you won't be slipping on eye protection. Mossberg makes some left handed shotguns designed for defense, but you may have to have it special ordered. Stag Arms makes AR-15 style rifles in left handed versions.
Hope this helps a little rather than adding to the confusion! Good luck!