I dive with my dad, and since I realize that almost all the wrecks are deeper than 60 feet, we we strongly considering taking the AOW class before the trip, also to get more comfortable.
A good idea. However, as several others have suggested, it will still not fully prepare you for ocean diving, irresepctive of depth. In part, the only way to prepare is to do it.
In general, the better wrecks, at least in terms of visibility, are a bit deeper, (~100+ft range). On a clear viz day, in the summer, in the Gulf Stream, you can have a phenomenal dive, not even notice you are at 100ft. But, you can also dive the same wreck on two different days and have a completely different experience. As several have said, there is a definite element of unpredictability that's not good or bad, it is just what it is.
Three suggestions: 1) Do the AOW as you are considering, and if you can add a Deep certification, do it as well. Won't hurt. Won't fully prepare you for saltwater diving, but operators - depending on who you go out with - may treat you differently if you show training / experience at depth; 2) consider your equipment needs - Herman already mentioned a 6ft SMB and whistle (which I endorse), personally, I suggest that people going of the coast on deeper wrecks carry a redundant air supply - pony bottle, not SpareAir; 3) once you have booked your trip, and know where you will be staying, when you will be in NC, you will probably be able to get more specific suggestions, about wrecks, operators, etc; Post your plans in this thread and you will get more input, and possibly even be able to link up with someone on SB who will be diving off the OBX that week.