How Old Am I?

Ever since I hit my forties, I cannot seem to remember how old I am. I always seem to think I am a year older than I really am-this causes my younger than me by two years sister much stress as she is constantly having to figure out if she is really as old as I am saying or not. Today is my birthday and she posted a comment on my facebook wall wishing me a Happy Birthday and asking that very question..now how old are you?