First- do I look like a lawyer to you? OK- now that THAT is settled- the law varies from one state to another. You need to know the law for YOUR state.
The original question related to Virginia, open carry, handgun, 18 yr old. This answer applies ONLY to those things.
Open carry is allowed in Virginia. No permit is required to carry IF NOT CONCEALED. Certain places you cannot carry- open or concealed- courts, prisons, schools. An 18 yr old CAN possess and open carry a firearm, including a handgun. They cannot purchase handgun ammo (Federal law applies)
My bill for legal services is in the mail. I also accept beer.
What we have here is... failure- to communicate.