Castiel was not there for the beginning. He was not present for the beginning of Dean’s life, culminating in his birth and Mary’s first real understanding of happiness. He was not present for his first step, the beginning of many, many more, nor was he there for his first tooth, the beginning of a full set that Dean would be proud to flash in haughty grins and loud laughter. Castiel was not there for the beginning of short-lived normalcy, but, worser still, he was not for the beginning of tragedy. If Mary was right in thinking angels watched over her children, he was not one of them- because Castiel was not there for the fire, nor the first hunt, nor the argument years later that propelled Sam to leave to college and Dean to fight monsters with his father and a grudge. Castiel had things to attend to- a heaven to fight for, a cause to defend. In his existence, time had no definition. Divinity is above time, separate from it all together. There was, to him, no due date for his entrance, no scheduled appointment for lives to change.