Yes, Palm reading is very accurate, and as you change your life's circumstances, the lines in the palm will change to accomodate those circumstances. It is ever-changing, just as life is. Nothing is for certain.
An example...the mount of venus..that is the meaty part of your hand below your thumb...(this is just an example of how these things can change) say it is really plump...well to a palm reader, this shows that the person has a huge capacity to give and receive love. Say, a couple months or years down the road you lose a job, marriage fails and you are totally heartbroken and you decide to become cold and hardened. This mount will begin to flatten, showing the change in that ability to give and receive love.
Another example...Your life line is a certain length showing your life expectancy...yet you begin to do things that are dangerous for your health or that may end your life sooner than your original life plan...you betcha..that line will become shorter...or certain traits of the line will change to show the health consequences.
So, yes...as with any form of divination...palm reading is a way of seeing what lays in your future on the day of your reading. As you react or act toward whatever you hear in a reading, so will your circumstances of your future. Just like with tarot cards. NOthing is carved in stone. Your lines and mounts change with your life changes.
I hope this helps.