The difference between greatness and mediocrity is quite simple. Mediocrity prompts a man to lower his standards to fit in. Greatness allows him to rise above circumstances to reach his potential.
Experience is a great teacher, but take caution with a pattern of thinking centered around perfect timing. Such a mindset will set you on a path of going in circles. Fear of making a mistake or not being ready may stop you from moving forward altogether. If you wait to feel 100% ready or until circumstances are perfect, the right moment will never come. Have a big vision, but don't just dream. Focus on what you can do today. The plan will unfold as you move forward. If faithful in the small things, little by little you'll build the courage to step into the big things.