This is a board for AAS, and bodybuilding is an AAS sport, so I doubt AAS is the last thing on your mind, but I will say, if that's your natural physique, I would just stay natural. You could use steroids and be a mild responder, and you'd never have natty status again, and your physique wouldn't be that impressive for a non natty. But if you stay natty, you'll always have a world class elite natty physique, based on what we are seeing now. And let's say you use AAS and respond well, ok, you could be a top level pro, but you'll be addicted to AAS your whole life, you'll never feel like your as big as you should be, and any time you come off AAS you'll feel small and skinny.
So I say enjoy what God gave you and feel confident and comfortable with a world class natty body building physique that is permanent, healthy, and yours forever.