14 years old and sick of being fat!!!!!!!!?

All of my life I've been "average" but pushing the overweight boundary, I'm 5'1" and i weigh 119 lbs, some of it's muscle, but definitely not enough of it! I have thunder thighs ( i wear a size 4 jean), I have flabby upper arms, and a squishy stomach. I want to be between 108-100 by spring break, if i do a vigorous workout daily, plus pe at school for 45 mins, and a diet including only water and low calorie gatorade to drink, fruit for breakfast, salad without dressing for lunch, and a nutritious dinner. Could I do it? And also what are other things i could do?