Clothes Swapping with the Teenager

My teenager wants a sweater like Miley Cyrus wears in some of her shows on Hannah Montana.  I don't know where to find those!  I did find some cute cardigan sweaters like this one:

Isn't this a great-looking sweater?  I'd like one for myself too.  One for her, one for me and then another for her and another for me. 

What I really can't wait for is in another year or two, my daughter will be pretty close in size to me (once I get down to my regular weight which I am working on) so I'll be able to wear her clothes.  I can already wear her shoes, which she hates.  She says that because I am MOM, I shouldn't wear her shoes.  What does that mean?