I was 18 months, my sim partner was 15, and he had prior 121.
Now that I am just about finished, I will say this... I wouldn't want to do it any faster, and I am glad I got to experience winter during my IOE, and other things that most people on IOE are never lucky enough to experience.
Be careful what you wish for, and study the crap out of that GOM and CFM. This job on the left seat is NOT your right seat job and working the tiller.