18M, how do I reduce ass fat ?

So for context. I’m currently a student. I used to be really fat till 2022, eat super unhealthy everyday. I sort of went into depression in 2023, lost a shit ton of weight. I’ve been eating pretty healthy from the last 1 year or so. My body fat has reduced in areas like face, chest etc but I am struggling with fat around the lower abdomen. I live in a hostel, so no access to any gyms, all I’ve got is space for runs and a resistance band. I will join a proper gym in may but I wanted some inputs on how I can work on myself rn. I feel really humiliated, my friends sometimes joke that my ass is really fat and I wanna change that. Please some suggestions 🙏🏻