Conclusions are based in time. We live in time. So any definition of success is bound up with time. With other things you can say, "Can I yo-yo? Can I juggle?" Usually you have a pretty small window in which to get your answer. Stand-up is different. You can't do stand-up for one night and say, "Am I a funny stand-up comedian?" In two months or two years you'll start to realize it.
Demetri Martin