How to achieve a super flat belly?

Please don't tell me that I'm too young to be asking this question please 'cause you if are planning to do so you might as well stop wasting your time and leave this page right now. I am still in my early teens, 14 years old. I weigh 85 pounds and I am 4'10". I know my weight is below average, but every time i eat, my stomach gets super bloated, and my waist would enlarge by 4 inches or so, and it not only looks bad but it's also really uncomfortable. I have trouble controlling my portions, although I do eat healthy. I'm pretty sure this is genetic/hereditary because both my grandmother and my mom have pot bellies even when they were underweight when they were much younger. My stomach isn't bloated in the morning, but it actually gets bloated while I eat dinner. I try to eat dinner as early as possible (between 4:30 and 5:30) so that my body would have enough time to digest all the food. As I said before, I definitely got this from my mom, and my dad also has a pot belly, so maybe the only way I can get a flat stomach is by getting a six pack? I don't know, but I'm willing to do this if I have to. I actually had a big stomach my whole life. I just wasn't as aware of it as i am now, and it really bothers me. I can't confidently go outside after eating a snack or a meal. I see many girls at my school and their stomachs are very, very flat and I wonder how they got them but I feel a little embarred to ask them myself. Please, I really need this to boost my self confidence. if you are an expert and this or had any experience, please answer. Much appreciated!