Saying that every successful people had a mentor isn't really accurate, first of all you must understand that not everyone's journey to success is the same, some made it by believing in themself without looking up to anyone and there are some that had a mentor. Having a mentor isn't a criteria for success but most people believe that it can help facilitate the process which is true. Before picking someone as your icon you should be very careful so you don't end up having the wrong influence. It's easy when you are learning from someone else's experience, it saves you from making some certain mistakes, having a mentor can make life easier but it's possible to succeed without one.