I can live without CCW until I'm 21. I don't like it, but I can live with it. I'd just want a handgun for plinking and maybe HD.
In most states you can buy an antique revolver firing modern ammunition when you are 18, or you can buy an "antique" replica cap and ball revolver when you are 18.
With the antique you will have a real gun, but if you want a reliable gun for HD and accurate enough for plinking, then you will probably have to buy an expensive one.
With the cap and ball revolver, which can be had for a few hundred dollars unless it is a Ruger, you can buy a cartridge cylinder for another few hundred dollars and fire regular centerfire ammo out of it since it is legal to "make" your own modern handgun in many states.
There are two very important caveats with both of these.
It may be illegal under Ohio law for someone under 21 to do either, and you would not be able to legally buy the pistol ammunition until you are 21 (federal law). However, if it is legal in Ohio for you to posses a handgun under the age of 21, and/or to make one, then you can either have your parents provide you with the ammunition, roll your own, or have a rifle that uses the same cartridge and purchase the ammo for the rifle when you purchase it to stay within the law.
Third caveat, I am not a lawyer and this is just my general understanding.