DD is 13 and I bought her first few bras a few months ago which she she has never worn as she says it feels itchy between her breasts. I then washed them in sensitve skin washing powder (tried Fairy and Surcare) and she stil hasn't worn them. When I bought her bras, she had only just started developing, but she really does need to wear a bra now 
I bought them from M&S from their Angel range
Any advice?