My mom wont let me have a bra what do i do?

It depends on how big of a bra you need. When I didn't really need a padded bra but I wanted one, I asked my mom and she said no. But, she did let me wear those un-padded training Bras, which helped. About a half a year later I asked her again, and she said okay. Just tell her you feel uncomfortable because people can see through your shirt. Hope I helped! :)