I'm not sure why nobody has suggested an Arbor Coda, but I'll be the first.
1) RC profile is not easy to learn as a beginner, and like someone else mentioned, you are going to take some really brutal falls. A few years back, I jumped on my first Lib Tech, a Jamie Lynn, which was naturally a pretty stiff board, but I certainly took a couple nasty falls at 40+ MPH that just jumped at me. Didn't know what had happened on my toe side until I had buried my shoulder into the hardpacked. 2 runs later, as confidence was coming back, I did the same thing. Needless to say, that is part of learning, BUT...
2) The Arbor Coda is their full rocker system, but very stable at speed, a nice amount of dampening, great pop for a rockered board, and a board that I would buy now if I wasn't fully after a Banana Magic this year, and I am 4 years in.
3) They have grip tech, which IMO, is better than NS vario grip. Some might disagree.
4) The board is a twin tip shape, but with a slight set back, which is going to be nice for someone learning, as most of your riding in the first year is going to be regular, before you start really exploring switch, and being a twin shape, this board is more than capable of riding switch.
Last - you can get this years model, which the only thing that is changing for next year is top sheet, for a nice discount, and your size should be available.
Overall, I'd recommend this board for all mountain riding over a true twin Proto everyday of the week. With a slight setback, you will be more comfortable early riding at higher speeds, and this board eats it up well even in the afternoon chop. But like I said, it's only a slight set back, and perfectly capable of switch. And the board, especially sized at a 153, is more than capable of riding park, and was a board I had no problem pressing.
That would be my pick for you. I love the Proto, don't get me wrong, but it is more of a freestyle board, than all mountain, and if you are like most people, charging the mountain and progressing to steeper stuff, you will appreciate that set back as someone learning versus a true twin with a centered stance.
Last, it is not a beginner board, but more forgiving than say a Proto. Just my thoughts.
You guys know by now I am not a spammer. Just trying to help someone out. REI has the 153 at 20% off, and the nice part about REI, say you don't like it, they have a no questions asked return policy. Meaning ride it, hate it for some reason (you won't), send it back, get a full refund.