Kartoffel,
I don't think I'm a beginner.
I'm working with 3DGS from October 2013.

I'm following DLively suggestion.As I said,My game's city will be like in Vice City,so it's not a clone.

A little city will be enough to test my game.

FEL,How do you know my game project will fail?

I'm not making a game like GTA V...

DLively,that's what I do now.

For example,I'm working on R.A.G.E. to be used in my game.

I like to share my works in forum,to be used in anothers game.