Castiel was your guardian angel, he watched over you since you were born. You were never alone...you cried, he was there, you hurt? He was there. At first it was all for a job since you were marked by heaven...but between you and him a bond was created, Castiel became fond of you more than he should have. He was like a father. (Given your family situation which was not the best) now you were 14, you were in your room studying.