The beginner/intermediate/advanced/expert board rating typically refers to how big/fast/hard the rider intends to go. A newbie on a stiff, cambered board may find more diffultly learning to turn and more likely to catch an edge than with a more noodley setup. On the flipside, an advanced rider trying to ride fast and hard on a soft beginner board will find it very chattery and prone to wash out. (Of course, when I started, everything was stiff and cambered.
The stiffest board I've ridden, from 155 to 185cm, was a 178 Oxygen Proton with hardboots. The thing was a beast to try skid around and manhandle in tight, slow, crowded conditions. In those conditions or in choppy snow, it would wear you out quickly! But, once you were able to open it up and passed a certain "threshold speed" on steeper/less crowded runs, the thing suddenly came alive and was a ton of fun with lots of rebound and fantastic edge hold. Of course you needed plenty of strength and stamina to maintain balls to the walls hard carving, but the board worked with you then instead of against you. It's very frustrating to try to rail like that on a floppy board.
Board materials and geometry have fortunately taken a leap in recent years to close the versatility gap. My current ride is a 182 hardboot deck, cambered, but with slightly decambered tip and tail. When carving hard with a high edge angle, the nose provides a quicker, more solid initiaion, while the entire length is engaged, providing phenomenal edgehold, and the tail releases easily. If the need to skid arises, though, the flipped ends are off the snow, so the board turns like one much shorter than it's actual length. Titanal layering means more chatter absorption, and less stiffeness. Hard carving edgehold is much improved, too, though you really need to bring your A-game with every hard-charging run or it will vault you into the trees. Most of the sidecut is in the nose, which flares to near straight in the tail; meaning you have to be very aggressive starting high in the carve because you rocket from the exit. Triply-so in tight conditions where high edge angles and tight carves are a must. Wicked fast ride, but you need to be able to control it.
I've never seen a newbie "molest" a black run, but if you're confident on that board, by all means stick with it. Perhaps you have some other "boarding" related background that helps.