I have already a Java calculation of age method. I have a Person Class where I have the method and I need to ask the current time each time the method is called. All I could do is make age a static field of person class, so all person classes use the same time now. Im worring about the Calendar.get() creating Calendar objects every time method is called. Am I doing it wrong? Can I make it better?

public short getAge(){

    now = Calendar.getInstance();


    return  (short)  ( (now.getTimeInMillis() -  birthDate.getTimeInMillis())/ 31536000000L);


}