If you are thinking home defense a 12 gauge with an 18 inch barrel and 6+ capacity is highly recommended. It was my first gun and it is the gold standard of home defense. And, it costs les then most pistols.
You can also use it for skeet shooting, which is great practice for home defense.
If money is not too tight then get a semi-automatic Mossberg 930SPX, that's what I have now. At around $600 it is a great fun and HD gun.
Experience is a very bad teacher because it first gives you the test and then teaches you the lesson.