losing weight as a teen?

Well, long story short.. I've been feeling the need to start cutting myself. I've never cut before and the feelings have been I'm my mind for about 2weeks, every single day. Tonight I found out its because I'm fat/ feel fat... in may I was 185 lbs, since then a few of my friends, mom and grandma told me I've lost weight.. I see a small difference. Anyways I decided to lose weight starting tonight..I did 30 jumping jacks and sit ups, then I danced for like half an hour then to close out I did 30 more sit ups. I was wondering if I use the "dancing, sit ups , jumping jacks, eat healthy, no soda/juice" and work out 4days.a week method will it help me lose weight and just so u know, I'm 14 y/o female, and I had surgery on my stomach when I was nine .. anyways willthe method above help me lose weight within a couple months? Thanks in advance