Within a couple of months of soloing I typically see "graduates" crashing their first plane.

Usually this occurs as they start pushing their comfort zone, or when they switch to a new plane.

Their trainers get a good going over by instructors, so they do quite well with them initially... however a bit of neglect or failing to go over the plane before flight, insures a crash.

If they are disciplined enough to get past this stage, then there is often a bit of overconfidence when that second plane is flown.