Yeah my first owned hand gun was a .45acp but I did alot of research and alot of shooting of different guns. For safety stick with a double stage trigger and by all means please attend a class. for those offering a .22 thats really weak and i would recommend to start with a 9mm as it is very easy to use and very comfortable. Remember this is for home protection not target shooting so you eventually will want a larger caliber. A .22 will just piss a robber off and probably get you killed... a 9mm will stun them and do some good damage. A .40 or .45acp will decimate the robber causing SIGNIFICANT tissue damage! .50AE will give them a heart attach and will be the wrath of God raining down on them! Not only that but anyone within 30ft without hearing protection will be deaf! Im not kidding about the deaf part... those Mothers are LOUD! If you have specific questions feel free to ask there are many of us here on the board who are well versed in firearms.
I personally like to use my 6.8spc M4 Carbine as my home defense. I was at the range last weekend and in an unsupported standing position got 20/21 head shots rapid fire @ 25yds all within the fatal triangle or just a tad to the left
Remember practice make perfect...