I'm 5'5 and 17 years old, i weigh 190.2 pounds i'm ready to lose weight but i want to water fast for 30 days straight ?

Not a good idea: Changing your feeding habits & engaging in an enjoyable exercise is the way you modify your weight in the long term. A 30 day fast is neither safe or effective in the long term. A visit with a clinical nutritionist could help you devise a healthy feeding plan designed around a weight loss of 1 lb/wk until you reach your desired weight. If you still want to do the fast be sure to write a will.