One of my favorite quotes is from John Piper:
"God does not call the qualified, He qualifies the called."
We have no need to despair because He knows better than anyone that we don't have what it takes to do this life. Without Him, that is! Our lack of wisdom, strength, or talent gives Him an opportunity to give us what we need. He can qualify us for the call- and this brings Him glory.
"And I am sure of this, that He who began a good work in you will bring it forth to completion at the day of Christ Jesus." Philippians 1:6
He has a plan and a purpose, and He has promised to bring it forth to completion. When we mess up, He will cover us with His grace. What we are lacking, He will give.
We have everything we need for today, tomorrow, and a lifetime of heeding the call of the Kingdom.