Ok I have a question.

So I and 13 and 5' 2" and all of my friends are in there period and have super flat stomachs. We are all the same type of active pepole (somewhat active but only when we motivated) and I have what i looked up us called a hormone belly its like no matter how much hacks to get a flat stomach on pinterest they dont work. And yeah I know all girls bodies are different but I hate it. I saw this really cute shirt last week but I didnt get it cuz it wasnt baggyy enough to cover up my stomach. Is this normal?. How can I get my stomach to be flat?