Dear Elizabeth,
It's true that girls are reaching puberty (the physical changes of adolescence) earlier these days. That means that when your mom was your age, she probably remembers that girls didn't develop breasts until they were 11 or older. Now, many girls are developing at nine. It's understandable that you want to fit in, so if your friends are more developed than you are and are already wearing bras, you want to wear one, too. Tell your mom that you might not need a bra yet because of your physical changes, but you do need one for social or emotional reasons. Ask her to go shopping with you, so you can show her that there are stretch bras that will fit you just fine—right now.