I understand your circumstances and think that once 18 you should be able to make your own decisions as an adult. Sure its legal that you have a pistol and ammo that has been gifted to you, that is fine and within the law. I know Being able to carry a pistol is comforting, esspecially in a bad area, [B]BUT[B], IMO I would not risk carring any firearm on your person weather it be, in your car, (glove box, under seat, etc.) open carry or concealed til you are 21 and get your carry permit. If you were to be stopped, and arrested you would never be able to do want you want to do in the near future. Even if you are correct, its probablly not going to stop the arresting officer to "do thier job." Police always say that they are just doing there job and you have to let the courts decide....... I know a couple years may seem like forever but we all had to wait til that 21st b-day to drink booze, buy a pistol and all other things "adults" 21 and over get to do LEGALLY.
Best of luck..... B.B.