In order to get an epidural you must be well into labor. Most doctors like to perform the epidural after the mother is about four centimeters dialated. Other doctors may base their decision on the amount of pain that you are feeling.
i beleave you my get a epidural as soon as you reach four centermeters dialated and when you get to the pointe that you cant take any more pain. but if im not mistaking it is as soon as four centermeters to get a epidural. it is well worth it too.