Shooting a gun is varied based on experience, First of all it's louder than you imagine. I would say, go to the range, practice with a 9mm or 22 because the bullets are cheaper and you want to get used to squeezing the trigger. Get a .40 or 45 for home defense, or better yet get a shotgun.
The thing is, if someone is going to break into your home, it's usually going to be someone you know who sent someone in there. Or a neighbor who knows your routine of leaving and returning home.
If you leave the home and your lady is there alone with your kid, make sure she knows where the gun is and always have one in the chamber before you leave the house, some women that aren't experienced with guns have a hard time racking them.
Get a conceal carry license, because you should have a gun on you when you walk into the house because if you walk into a situation where someone is in your house, you are not going to have time to get to your gun hidden in your room, or worse yet, the robbers have found the gun. It's best to have 2 or more weapons in different locations.
If you live in a high crime area, it might be wise to move to a different area. The last thing you want to do is get in a situation where you have to shoot somebody and then have detectives and lawyers and juries involved. Be safe, be careful