Suggest Treatment For Hurting In Nipple

I am an 11 year old girl. I weigh about 67 lbs. I recently grew 3 inches taller. I have grown hair in certain places meaning puberty has started.My nipples were hurting starting 3 months ago, and stopped hurting last month. When I look at myself in the mirror, I see something on my chest sticking out of my clothes, and you can see my nipples. The only thing is that I am not sure if my breasts are big enough for a bra. My mom hasn't said anything about a bra to me. She recently said that I went through a growth spurt, but I think she meant height. I feel uncomfortable and nervous asking her about it. My breasts have started developing, but should I talk my mom into getting me one, or just wait a little longer for them to grow more until she notices?