I see what's going on!
My Mum had an idea of what I should dress like, based on her life, but I had a sister who was quite a few years older, so it was kinda inbetween...it's nice that your Mum actually takes notice though Hon, But seriously, that's what Mums do! Let her down gently, by showing her 'net photos of what other people your age are wearing, i.e Miley.
Or, show her what Britney was wearing at your age, lol. You could always admit complete love for Lady Gaga, then retract your statement when she's bowed to your terms, :-D