Walter,
60' is deep? Egad, I have not looked at the PADI AOW course recently, but do they really consider a 60' dive a "deep" dive? If so, I was doing "deep" diving from the very first post-OW-cert dive.
I really have not thought too deeply (no wise cracks, please) about the definition of "deep", but I usually put dives in the 100+ ft category as "deep". I know that it is all subjective since you can drown in 6" of water or get the bends by coming up too fast at depths less than 100'. At any rate, I sure would not do a whole lot of serious deep wreck diving w/o a little more experience....
Joewr