I can't give you any real world experience because my car is under 300 miles right now but I have been reading the forums for a while. I didn't think you could actually activate proper launch control until 1200 miles+. Did you actually get a checkered flag to show up? It's definitely recommended to take it a bit easier until then in general.
With that said — was the car warmed up? What kind of tires do you have on? What's the weather like? Was DSC off and what mode were you in.
Here's a post about setting up the car for LC for reference:
https://g30.bimmerpost.com/forums/sh....php?t=1457736