The Orc is definitely not the worst choice for a beginner, especially in DX. But I'm guessing MarkDSM is saying this because of speed. The Orc is a fast disc (speed 10) and is reasonably "overstable" (pretty low turn at -1 and reasonably high fade at 3). Your Skeeter is only speed 5, so there's a pretty big jump there. The Valkyrie is still a speed 9, which means you need more "arm speed" or power to make it work than you would with your Skeeter (or Dart). I'd say look for something in the speed 6-7 or maybe 8 range first. Everyone seems to recommend the Leopard for new players, and a TL would be a good alternative as well.
Many new players have the experience of trying to throw higher speed discs, then they find out they can throw a Leopard or even Teebird just as far as a Destroyer or Boss or Nuke. Sure, the pros throw those fancy high speed discs much farther than fairways, but for newer players there's usually a lot to be gained just by working on form with fairways. I don't think we're trying to discourage you from trying the Orc, it's just that there's a lot of room between those two discs that you might benefit from exploring.