Your first day you will probably hate it, your wrists and tailbone will be screaming. But, like Wasatch said, go rent first. I would recommend a camber board for beginners as they will be catch free and easier to turn. I really don't think you want to go all out for a NS for your first board.
My first board was/is a GNU Carbon Credit I got for a pretty good price at the end of last season. Trust me, this board to me is a great beginner board and will be something I'm not going to grow out of talent wise for years.
Definitely try before you buy. Check with the pro shop at the hill you ride and see if they have a camber board you can demo. Do tons of research before you buy and remember to spend the most money on your boots, not your board. You should spend the most on boots, then bindings, then board... in that order.
2011 GNU Cargon Credit 162w
Usual Riding Spots:
Paoli Peaks, IN
Perfect North, IN