I Am 5ft 4 Inches And 15 Stone Is This Too Fat?

You weigh about 210, correct?  This is a little overweight for your height.  But you may be built differently and carry it well.  If you're trying to lose weight just start by giving up a few things.  Say to yourself, "Self, I am not going to drink soda from here on out.  I will have water, tea, or light lemonade instead."  STAY AWAY FROM FAST FOOD!  I did this and lost 5 pounds (even though I wasn't trying to).  Incorporate a bit of exercise.  While you're watching TV pick up some weights, can, books - doesn't matter, and lift them up and down as much as you can.  If you do this casually over a half hour or so you could burn up to 90 calories.  Trun on some music when you first wake up and dance to the whole song (this can burn up to 30 calories).  Park farther, take the longer way, take the stairs - all this adds up.  My mom also had a weight problem until she started doing these things.  She weighed about the same as you and is now down to 160!  She looks great!  And it took her 4 months!  When you're in the bathroom, jump up and down as you're washing your hands or do s ome squats.  When you're in the car waiting for someone punch out in the air in front of you for as long as you can stand it.  IT ADDS UP BIG!  And don't forget to drink water.  Decide if you're really hungry or are bored and just looking for something to do!  BE STRONG! 
 
BEST OF LUCK, SISELE!!!!

If you mean that a stone is 14 lbs then you weigh 210 pounds . Yes that is too heavy for your 5'4" frame. Unhealthy would be for you and your doctor to decide. The diet thing  does not work . You have to change your way you eat and what you eat. In other words make a life change/choice. You need to talk to a dietitian and set up a plan with all the foods you can eat without cutting out the variety of foods you eat. And from what I hear plan for a cheat day where you can eat whatever you want without feeling bad after eating it. This will help you keep on track and become healthier and lose the weight over about the same time it took to put it on.