Creatinine clearance (est) l 73.3600 ml/min 75.0 - 115.0: why is my level low? is it because i'm a small 64/ female and eat no red meat?

Realize: As we get older out kidney function does slowly decline. Think of the kidney as being made up of a million Brita filters. As we age, some of those filter stop working. If you have blood pressure, cholesterol, and/or other vascular issues even more of these filters can stop working. Be aware even your diet(as you mention) and/or muscle mass can affect this value with suggestion of a problem.