I bought a GNU CC as my first board as well and went riding the past 2 week ends without any de-tuning.
It was a little catchy but I didn't feel that was holing me back. And I loved the magne-traction (I'm on the icy east coast).
Overall very happy with the board.
If anything, I'd say you should have realistic expectations about your board. It will definitely be much better than any beat up rental you've been on but don't expect to be bombing blacks diamonds by the end of the day either
I'm sure Panhandler's advice is good, I'm just saying that it's by no means a deal breaker if it's not de-tuned for this week end.