Fasting for 100 days

Hi,

I read online that one woman fasted for 90 days and lost a lot of weight. I am starting my long Water Fast tomorrow. Is 90 days safe to water fast? Am I going to have lose skin ? I am 5'06 and 140lb, however, my body fat % is very high: 33%. I was always about 13-14% body fat, and my weight was about 115 lb until this fall. I felt into very deep Depression and binge eat for almost 4 months. As a result, I gained a lot of weight and my body fat % changed dramatically. I do not want to go to gym now, because I've never in my life had to exercise to lose weight. Therefore, I would rather lose a lot of weight just by Water Fasting and will start going to the gym after the fasting. How long will it take me to get back to 115 LB and 14% of body fat with the water fast?

Please advise me.
P.S. Do I need to exercise during the fast? I also read that a lot of people just rest during fasting because they can lose more body fat. Is that true?
Thanks,