"Knowing your strengths and weaknesses is a strength."
"You need to be brutally honest with yourself about what you can and can't do on the horn."
Honest appraisal of one's abilities is the first step in improving any skill. The key is constantly practicing both the things you can do and the things you can't do so your assessment of your own abilities is not out of date.
Do you have an accurate assessment of your strengths and weaknesses today?