When I started my DM course I had just under 100 dives, actually I started it and then went on vacation to Thailand where I reached the 100 dives and resumed the course after coming back home.
This happened in October last year, the papers were sent in February, just about two years after my very first certification dive.
Was I ready?
NO
Was I aware of not being ready?
More than vaguely, but my instructor surreptitiously accused me of underestimating myself.
Would I be ready now, about 50 dives later, to guide dives for money and fun and do it safely?
No, I'm just about learning.
Please BEWARE: when your certifying instructor says you're ready to get your card, please follow your instincts, and if possible go and get the unbiased opinion of another instructor from the same agency, be it PADI or something else, but it has to be the same agency so standards are known and understood.
The instructor I certified with has been referred to PADI, one of the reasons (not the main, though) is his incapacity to prepare me; I just hope he will be stopped before he does any real damage.