How should a girl tell her parent if she thinks she should start wearing a sports bra?

If you haven't asked your mom to buy you bra's yet this is what you should do.

Get all the courage you can, make your statement as clear as you can and ask your mom if you can talk to her, go into her bedroom and sit down on the bed. Say "Mom, I was wondering if you can buy me bra's. I think it's time for you to buy me some." If she doesn't agree that you need one, ask her for training bra's. If you can't get the courage to ask her in person, write a note and put it in her purse. She will soon notice it and she will probably ask you when you want to go buy them. I would prefer the note, if you can't get the courage.

I have the same problem but i am too scared to ask or wright a note

I don't want to tell my mom I'm embarrassed