Weight loss goals advice? reasonable or not?

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Hi, so I'm 19 and about 183cm tall and weigh 109 kg, I started at 115 in November and have been going through my weight loss journey if you will and still have a long way to go. I recently started working out instead of just dieting and was wondering how much that would help my process? My goal is to hopefully get to 100kg by March and 90kg by mid July. I would eventually want to get to 80kg and I'm currently aiming for October of 2014. Is that reasonable or not? Advice?