Can I now purchase a gun as an adult, if as a juvenile I was convicted for having one in my possession?

Several issues exist here. 1) Was your juvenile record sealed or expunged? If so, then you may not have a juvenile record anymore and the gun possession charge would no longer exist. 2) Were you charged as a juvenile or an adult? Although you may of been a minor at the time of the incident, if you were still charged as an adult, then the conviction may still appear on your criminal record, which could prevent you from purchasing a new firearm in your state. 3) Was the gun possession conviction a misdemeanor or felony. If the conviction was a felony, and still appears on your criminal record as a felony gun conviction, then felons are not allowed to possess a firearm. Before you attempt to purchase a firearm, check your criminal history first to address some of the above questions.