You do not need to have a mentor before you can become successful in life. There are many successful people in life that does jot have a mentor.
Some people only like after a role model and they may want to be like such people and work towards it.
But know that success is not about having a mentor or looking after someone as a role model. It is about how smart you are in achieving successes. Opportunity and exposure are also very important.
You are absolutely right, having a mentor isn't a criteria for success, you can become very successful without having a role model or any one you look up to. Achieving success is all about dedication and consistency to you goals and ambitions. As a matter of fact having a mentor without having a drive or prospect would take you no where. Some people are of the opinion that having a mentor isn't necessary and believing in yourself and working hard is the only thing that matters, it's not entirely correct but it actually makes a lot of sense.