You don't know OpenGl or DirectX? You should know at least 1 graphic-Api or things will be complicated.
I don't know what you mean with "the logic of creating 3d models". Just create the model with a 3d Modeling Software like Blender and import it via your Graphic-Api.
If you want to learn about the Game-Logic itself, you should just start to create small games to gain more experiences.
I kinda disagree with this. You can learn those if you're trying to get a more in depth understanding of how things work, but if your goal is to get up and running as fast as possible, something like Unity would be best. If you grab it before tomorrow, you can get the Android and IOS versions for free (they have a sale going on right now).