You are only 34 pounds from your goal. From everything I've read as you get closer to your goal the weight comes off slower (so don't get discouraged). I can't say if you can lose 15 pounds by the 26th, it depends on you and your body. But you can definitely try! Just strictly follow the book, drink plenty of water, begin exercising (if you don't already) and keep us updated!
Good Luck!