I would say that the stock pad is good enough for a begginer on the track. I still have stock pads and used them on the Nurburgring, this is a 12 mile course and I was for my first time on the track very brake happy with my car to say and I had no brake fade towards the end, just some metal ticking and heat waves.
I will at somepoint upgrade to a better system being that this is technically the weak point of our car.
Stick with what the others say on here and just learn with the stock pads. You will not notice a significant difference from one to the other at this time in your drive to push the car to its limits, safely.
EDIT: JUST NOTICED YOU PURCHASED ALREADY. MAYBE SAVE THEM FOR LATER.