My mom wont let me where a monokini/bikini?

My mom absolutouly wont let me wear a bikini. Then when i asked her if i could get a monokini since its more modest and its cute she said no! They dont even sell onepieces in stores for juniors and i HATE Tankinis because there so unflattering and the get like blown up when i am in the water. She said she would rather me where a wetsuit then ever be caught in a bikini. I really like monokinis and bikinis and i tried to calmy talk to her and explaing why i like them. But i looked online to see if they have one pieces for juniors and they dont only for kids and adults. Please help!! I would rather be not swimming then in a tankini pleasee!!!! BTW i am in 8th grade