but in my case i will only use the 3 motors for the axis 1 motor for the extruder and last the hot end,
Those would be stepper motors, and you need the exact same number as any other printer, unless you want dual extruders.
I won't say forget it, but making a 3d printer is no trivial task. It's not exactly a beginner project. What shield do you have? Does it fit the Mega or Uno?