How to lose weight the healthy way?

Hai :P
I’m a 13 year old girl who is 4ft11 and weighs 103lbs
I want to lose 5-10lbs before summer but in a healthy way but at the same time making my stomach flatter.
I currently do 6 dance lessons & 2 swimming lessons a week and I only eat one meal a day with 2 snacks.

Any suggestions?