As some folks have said a basics class is a very good start. Also, buy snap caps and possibly a laser target system like iTarget or similar and get a dry fire routine down between range sessions, it will really help your range days be more efficient and reduce ammo use (which is critical these days). Of course, safety is extremely important here. Keep the live ammo in a different room and check, check, and check again that you have the snap caps/laser in the chamber and an empty mag. Every time. Complacency is your enemy. Comfort and "natural pointing" will be useful on a first gun, because you want something comfortable you'll desire to keep shooting, same for a trigger that "feels nice" (completely subjective). Anything can be made to work with enough trigger time, but to start comfort will help ya keep at it. A full size is more challenging to carry but far more comfortable to shoot, it might be worth, if carry is a possibility, considering the compact size guns, like a Glock 19 or similar size. Still very pleasant to shoot and easier to carry when needed. Most will accept full size magazines and grip sleeves for HD/nightstand duty. Even in these crazy times 9mm is a good choice. It's still the cheapest and generally most available service caliber and will get the job done. From your choices, and I've owned M&P and XDs as well, I favor the Glock, but that's subjective and all are good guns. In a vaccume, just starting out knowing what I know and like I'd personally favor the HK VP9, but they are all so close. Beretta APX makes a high quality, comfortable, good trigger at generally a lower price, so that's worth looking into as well.