Gymnasts! Will this make me skinnier?

hi so I'm a 15 year old girl and I want to become thinner over the summer. I am 5'3 and I measured myself as about 38-29-37.5 and I want to make my waist smaller. my mom signed me up for a gymnastics camp that goes from 9:00-12:00 four days a week for 6 weeks. I know I will get stronger and more flexible because we have had practice for 2 weeks now but I was wondering if I would get skinnier too? Like I have chub on my tummy that I wanna get rid of and a little on my thighs. I can already feel I'm getting stronger but I'm worried that it's just muscle building up under the fat :/ anyone help?(: thankyou guys(: