Looking to lose about 15 pounds; need motivation and supportive friends! :)

My name is Stephanie. I'm 20 years old, and I weigh about 135. My goal weight is about 120, and I've tried getting there before, but I'd lose my motivation and gain weight back. I'm counting calories religiously, and working out whenever I get the time. I'm hoping that by sharing difficulties, and hearing others' success stories, I can keep it up this time! Thanks!