The following three verses emphasize God's omniscience:
O Lord, you have searched me and you know me. You know when I sit and when I rise; you perceive my thoughts from afar. You discern my going out and my lying down; you are familiar with all my ways. Before a word is on my tongue you know it completely, O Lord.
For a man’s ways are in full view of the Lord, and he examines all his paths.
Aren't two sparrows sold for a penny? Yet not one of them falls to the ground without your Father's consent. But even the hairs of your head have all been counted.
So, if Rhonda Byrne (or anybody else) believes that a) she is God and b) The Secret is compatible with Christianity, then they ought to be able tell me how many hairs are on my head (a task which, I admit, is getting easier and easier every day) and she also should be able to tell me when a sparrow has fallen to the ground. And she should be able to know my thoughts from far away and she ought to know every word I speak before I speak it.
If she (or anyone else with her understanding) does not know these things then her belief that she is God is false. Now if she were to insist that she IS God in spite her obvious lack of omniscience, then she has a view of God that is, by definition, contrary to what Christianity (via the Bible) teaches about God.
So if she claims to be God, but lacks omniscience, then either she is not God or she has an understanding of God which is incompatible with and contrary to Christianity. She can't claim that "The Secret" is compatible with Christianity and then claim that she is actually God while at the same time demonstrating that she lacks the Christian God's attribute of omniscience.
Rhonda Byrne is not God, and neither are you.