Belly piercing, difficulty with parents?

so i keep asking my mom if i can get my belly pierced and she hates the idea of it. And i also tried to make a deal with her by getting good grades which i do anyways but she still said no. I was just going to get it anyways but im afraid she will see it. And plus i sprawl (slide on the floor) during volleyball alot which is happening soon. I just want my belly pierced ): any suggestions please?