Are you positive you are on flat ground? My car will roll forward the same way if its not perfect. It seems I can only engage launch control 5% of the time because of this.
Your steps are correct.. oil temp needs to be at normal temperatures as well otherwise it won't work, but if the checkered flag is coming up, then it should be working fine. Are you actually seeing the flag? How is the car moving like the clutch is slipping? Can you describe it better?