I feel like I'm not making any progress?

I'm a fifteen year old girl. It has been two weeks since I started to eat less/healthier and exercise a lot. I climb stairs, play handball/basketball, badminton (competitive), jogging and walking. Yes, I do feel a lot thinner, I'm dropping sizes but I have only lost 1 kg on the first week, my weight remains the same on the second week. My friends said I'm a lot thinner now. I weigh 136lbs now and I'm 5 feet 4. It surprised me that I weigh more than my 'fatter' friends, maybe it's the muscles (I play a lot of sports all the while, I'm pretty active). I'm not denying but I'm not fat, I just want to be thinner and have a smaller size body. I have broad shoulders so people call me 'big-sized'. I don't know what to do, I tried very hard but I'm not losing any weight? My other friends lost a lot of weight (around 2-4kg) but I'm not? I feel hopeless.