In Ohio, you have to be 21 to purchase a handgun, but you can legally open carry a firearm at 18. If I were to receive the firearm as a gift, could I carry it?
Open carry is a bad idea for a multitude of reasons. First, it makes people nervous. Second, it makes police nervous -- and when police get nervous sometimes they kill people.
Generally in Ohio, when police arrest someone for "menacing" or "inducing panic" when they have an open carry weapon holstered, those criminal charges can be dismissed -- but why go through the risk of getting shot, or arrested, or having to pay thousands of dollars to an attorney. Best bet is to wait until you can obtain a CCW license.