body positivity

i’m a 17 year old girl who has a slight tummy and have recently noticed a double chin growing in. so many people say it’s nothing to worry about, but it’s been one of my insecurities for my whole like and i finally wanna start doing something about it this year. does anyone have any workouts to try and get rid of it by summer? i would do cardio but i have bad asthma so it’s very hard for me to do that