Won't hurt anything. The engine was pre-run before you ever got it. They are pretty much broken in in less than 50 miles anyway.
When I buy a new car, I leave the lot with my foot in the floor, always have. My dad and plenty of people I know do the same thing with no consequences.
The engine does 95 percent of its "breaking" during the first 5 minutes it runs. Floor it, you can't hurt anything.
Now it may loosen up over time and run a little better, but that shouldn't stop you from running it hard now.