John 15:16 (NASB)
"You did not choose Me but I chose you, and appointed you that you would go and bear fruit, and that your fruit would remain, so that whatever you ask of the Father in My name He may give to you.
When you understand that you are God's choice, you will become comfortable with His purpose for your life. God doesn't choose from the same aspect as man. The reason why you are struggling with accepting His plan for your life is because you are looking through your eyes. When you look through your eyes, you see failures, mistakes, and dumb decisions. You must understand that God's view is from a different perspective. His view is from an all knowing perspective. He knows His plans for your life, and your life moments didn't alter His plans. He previously prepared for your set backs.
When God looks at you He doesn't see you, but He sees Jesus. Remember the cross was an act of substitution. He stood in the place where you should have been, took your punishment, and endured so that you would not be seen as your carnal self, but because you are now blood covered, you are hidden by the blood of Jesus. This is why God can choose you and not take your past into consideration.
If God isn't dwellling on it, then you shouldn't. Make it your purpose this week to eliminate any thought that will try to assassinate the plan of God for your life. Speak life over yourself and begin to confess daily "Lord I thank you for choosing me". As you say that it will resonate in your spirit. Accepting God's choice means accepting YOU!