Like many questions raised on this board, a similar one has been asked before:
success rate for dayhikers and backpackers? But your question is about 1st timers. I think the numbers are a little lower than all timers, but not by much. It is my sense that the vast majority of those climbing Mt. Whitney are 1st timers.
Of course, repeat climbers--especially those who go up several times a year--have success rates that are much higher. (Mine is about 91%, including winter climbs.)