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 right, no one needs a mentor to become a successful person in life, many people who have become successful person today did not have mentors and they made it, although it is not bad to have a mentor because the mentor is like someone who will guide you through some things this day's there is not a good mentor again, anyone who wants to be your mentor will want to be having his share in anything you achieve because he will be thinking he is the one that makes you succeed.
It will be good to learn from someone but you have to learn how to succeed without the help of anyone sometimes, I once had a mentor but we didn't stay long because the starting from mentor took me as his delivery boy sending me up and down and that is not what mentor is about, learn how to succeed in life without anyone and no one will come and said it to your face that he is the reason why you become something in life.