The road to mastery has many mistakes.
The hardest part of learning Kung Fu is that you are going to make mistakes and you are going to be wrong most of the time. Many students feel that if they are making mistakes, then they are failing in their practice and they think that maybe Kung Fu is not for them. The ONLY way you can fail in Kung Fu is by quitting. What you need to remember is that every mistake brings you closer to mastery. As long as you do the very best you know how and keep trying to improve, you will get there. Everyone is on their own personal timetable and at their own personal skill level. Your rank is a reflection of your personal hard work and the time that you have put into your practice.