Ah, getting a little clearer.
What level of programming experience do you have?, that will determine your ability to follow through, since it appears you will be working in 3D, it also appears you will have to have some 3D modeling.skinning and animation skills.
Special effects in 3D will be another major component to the overall game design.
Audio components will be required as well.
If you create a folder and start creating snippets that will be useful to your overall game, you are well on your way to creating your dream.
If this is your first adventure into game development, I might suggest you start a little smaller.
There is also nothing wrong with making smaller games that have the coding essence of what you require for the larger game.
There is currently a lot of tools that will do the components your thinking of, outside of a collective program. If your also going to make and editor, that generates the game, I've been down that road and it takes a great deal of skill and patience.
It means you have to write an editor that spits out the game code, then you can test the game code for optimization, finally once the editor is re tweaked with better exporting code, you should have a structure to build upon.
good luck, its a lot of work if you have just started out. take my advice and start smaller if this is your first time, but make sure that everything your doing can be ported to your final larger project.
