Is it possible and healthy for me to lose 50 pounds in 3 months by following this diet?

Im a 21 year old female, im 5″11 and I weigh 255pounds? Is it possible for me to lose 50 pounds in 3 months? I’ve started taken this natural dietary supplement called proactol that decreases food cravings, suppresses appetie and reduces calorie intake. I started eating healthy, I drink plenty of water and I’m starting to exercise 5 times a week. So with all of that said and done, is it possible for me to lose 50 pounds in 3 months? If I go from weighing 255 to 205 pounds, will it be noticable or not really? Another question, is it better for me to exercise in the morning before work? also I want to start eating 1200 calories a day, is that ok?