I personally hate derringers. Some of the most unsafe guns made. Especially if it's going to be your first purchase at 21 years old. Take a look at the s&w governor if you want something that shoots .45lc and .410. Otherwise I would look at a better pocket pistol such as a kahr, s&w shield, XDs, or another snub nose revolver. There are a ton of them to look at. See what feels good in your hand as this in turn determine how accurate you are with it.