Rotten
Your instructor is nuts. Never go into a spin at 3000 feet. That is too low over the ground, let alone amsl. Military teach 3000' agl as a minimum height by which to recover (jettisoning the aircraft if this is not achieved). Seems a good plan to me. Add an appropriate amount for the recovery (depends on aircraft) and some for the turns (depends on a/c and number of turns). Sounds like a minimum 1000 feet for what you did. I tend to use 5000' amsl (QNH or RPS) as an entry altitude, over ground at less than 300' or the coast (never over open sea or any other monochromatic surface!).
Notice that your instructor's requirements are to plan to recover from a stall by 2000' agl, and teach you to recover by 3000' agl. To be recovering from a spin at around this level is extremely dangerous.