Or just use RD to make a portrait and coat-of-arms, then open uncompressed save game and edit your character. Basic text editing isn't really that hard even to someone who has never done any game modding himself.If you're abusing the ruler designer to make OP characters (which I always do) then just open the defines.lua and change the ruler designer age modifier.
Or do it the more irritating way and use event console commands.
That way you can have any character from a lunatic imbecile to a living god.