1st-I would suggest a gun handling/safety coarse for the beginner.
2nd- I would not suggest a pistol (semi-auto) for just home defense. To complicated, unless you & your wife are willing to get training and spend a lot of time/money shooting at the range getting familar with that semi. That HK is just to expensive to be just lying around the house for protection. Instead, a 12 ga or a 20 ga. pump shotgun. They are simple to operate, easy to point, quick to master, and a lot cheaper than any hi-tech, tactical side arm. Just my humble opinion. Good luck to you and your wife.