Losing 100 pounds in 3.5 months?

ok so im 14 Male in 6ft 1inch tall and I weight 286 pounds.... According to the charts im obese... I want to lose 100 pounds, Now my deoctor told me obese people lose weight 20 times faster than non obese people. on the On biggest loser a guy lost 243 pounds in less than half a year. so yes this is possible... I went from doing minimal activitys to walking up hill and around for 4 hours... then I do sit ups leg stuff and lift weights for one hourl..... and I abloutly stoped eating pop and juice (Iuse to drink 1-2 can of pop per day) I just drink water with some lemon.... I stoped eating bad breakfast (toaster trudals, slim jims) lunch (deep fryed hot dog, fish deepfried, pizza), supper I have less serving than filling up my plate 2 times like I use to.) Is what im doing helthy just to change like that in one day.. My mom warned me about schine splints but I dont have any..