Don't we all do this sometimes? When God calls us to something big, it is so easy to come up with excuses for why it won't work. The funny thing is that God doesn't just call in the cheerleading squad. My pastor noted that when Moses said he felt inadequate, God didn't start telling him, "Moses, you are totally adequate! You can do this!" No, rather, God simply says, "I am enough."
We don't have to be good enough, smart enough, brave enough, or strong enough, because we have a God who is more than enough. In fact, it is good for us to be weak, because then we will realize how truly strong he is. So if you know that God is calling you to something today, I encourage you to stop making excuses, and trust in God, who is bigger than all your inadequacies.