It's not only how fast you played or how loud the organ sounded. It's not only how few mistakes you made or countless hours you put into the preparation for it that matters. It's not only how colorful you managed your registrations to be or how well your hand and feet coordination was.
All of it is important but here's the key element without which everything falls apart:
Did you expose yourself to shame, vulnerability, and fear?
Are you able to embrace the feeling of not knowing what you're doing?
Are you willing to look like a fool?
You better be or in a world of billion choices nobody's going to care.