Knife Edge requires very little power and trainers often have a fuse layout that is well suited for knife edge. Hovering on the other hand is a different matter. I too have a trainer that will hover, but I'm not exactly a beginner and the trainer is on steroids big time (Kadet Seniorita 25 size, modified controls, with a YS63 burning 30% nitro hidden in the nose.)

LionHeart, I agree with Minn on 3D. 3D flying is in its infancy, and there is a lot of confusion about maneuvers and what 3D is, even between established 3D pilots. But in general, IMO, 3D is aerobatics that can only be performed in a stalled (harrier, blender, wall) or near zero/zero airspeed (waterfall, hover, TR, etc.)