MedGrl,
It is nice to hear another person is about to join the proud club of gunowners.
My recommendation is to start with one gun and build up from there as you feel need or desire. That will also be easier on your wallet and create less confusion.
Since it will be only one gun with dual purpose (training/self-defense), IMO the best all-around calibers are 9mm for semiautos and .357 for revolvers. 9mm is an excellent compromise among power, recoil, availability, and price. The .357 can fire the more powerful .357 for self-defense, but also the .38sp that is less expensive and kicks less, making it better for target practice. Other calibers are either smallish/weaker for self-defense or too kicky for your average novice.
Between autos and revs, I think semiautos with single-action triggers are better for a novice because the trigger pull is very low and thus it is easier for a novice to keep the sight picture and learn the basics faster. That is especially so if the same gun is to be used by the same novice for self-defense. It is true that revolvers with hammers can be manually cocked and fired in single-action mode, but it is not realistic to do so in a self-defense scenario, especially by a novice. Finally, IMO revolvers take more maintenance (than the reliable makes of autos) and more things can go wrong with them if not serviced properly, which is something of a liability for novices.
As to specific manufacturer recommendations, I think the best one can do is keep it inexpensive without sacrificing quality. Thus I would recommend Ruger - well-made, built like tanks, excellent customer service, American-made. You can expect to pay 350 for a new Ruger auto or 450 for a new Ruger revo. By comparison, new German and Austrian autos are in the 500-800s, Smith&Wesson revos are 650-900, Italian are ~ 800, and American manufacturers make 1911-style .45's around or above 1,000.
In any case, you have to figure out which gun is comfortable in your hand. To do so, it is best to take a self-defense course at your local shooting range to learn the basics, then rent as many guns there as you can and shoot a bit of each. Very quickly you will then narrow down the platform and caliber, and then the make and model you feel is a best compromise among all factors. Then practice, practice, practice.
Good luck and let us know how it went!