My is my child so eager to get bras?

She's 10, she has quite a little chest, but still I guess eligible for bras, but she's always looking through my bra drawer, and she always sees her big sister who is 13 with bras on, and she takes her bikini's, and it's just ridiculous, should I get her bras? Training bras? Real wired bras? What is with her? Why is she all antsy to get them, she's only 10, idk? Plz help, thnx sooo much!! :D :D