I didn't start writing a game code yet. I only think over implementation.
We can't tell you much without seeing the full code.
Premature optimization is the root of all evil.
Well maybe not, but on a more serious note; you should focus on getting a sound architecture and deal with any potential performance related issue when (if) it comes. Truth is you don't know enough about any potential issue to solve it until you've seen it. You are just as likely to introduce problems as you are to fix them should you do it now.