The book of Jeremiah opens with God telling this priest named Jeremiah that he has been ordained from before time began to be a prophet to the nations. Comfortable with his position as a small-town priest, Jeremiah immediately tries to dissuade God by offering up two excuses of his own. Here's the exchange:
The word of the Lord came to me, saying,
"Before I formed you in the womb I knew you,
before you were born I set you apart;
I appointed you as a prophet to the nations."
"Alas, Sovereign Lord," I said, "I do not know how to speak; I am too young."
But the Lord said to me, "Do not say, 'I am too young.' You must go to everyone I send you to and say whatever I command you. Do not be afraid of them, for I am with you and will rescue you," declares the Lord.
Here comes the Maker of the Universe to this young priest, telling him, "I knew you before you were even conceived; since before time began I set you apart as a prophet." And how does Jeremiah respond? He says, "But I don't know how to speak, and I'm way too young to be a prophet." God paints this massive, cosmic picture of calling Jeremiah to be a prophet, and Jeremiah offers two excuses as to why God must be mistaken: I don't have the ability, and I don't have the experience.
It's funny how God responded. He didn't say, "Oh Jeremiah, c'mon, you're an excellent speaker. And you've got plenty of experience to do this job. Stop being so modest, you silly goose." No, God simply says, "Don't say, 'I'm too young.'" He doesn't coddle Jeremiah; he commissions him. "Don't give me any excuses, Jeremiah. You're going to go to the people I send you to, and you're going to speak the words I give you."
God doesn't accept our excuses. Jeremiah lacked the ability and experience to be a prophet, but that didn't stop God's plan for him. Don't let your excuses short circuit God's call on your life. If he's called you to something for which you feel unqualified, then he either made a mistake (which he didn't) or he will make you qualified in some unexpected way.
This is how God qualified Jeremiah for the prophetic office: "Do not be afraid of them, for I am with you and will rescue you." The simple truth is that Jeremiah wasn't qualified to fulfill God's call on his life, and neither are you. The only thing that makes God's task possible is his presence with you. If you're succeeding based on your ability and experience, then you're not dreaming God's dream or answering his call for your life. God's call on your life will be so far beyond your ability that it will demand his presence to accomplish.
Don't settle for anything less than God's most difficult task for you. Be aware of your limitations, but don't let those be an excuse to run and hide from his commissioning of you. Lean into him. If he has called you, then he will be with you.