My little sister thinks I'm beautiful

As I handed my sister lululemon leggings today
And watched her wriggle into the waistband, she did not
See me wipe away tears with thick and dark denim
As I watched my smart, talented, cruel little sister who should never be looked at as just beautiful
Try on piece after piece of fabric getting smaller and smaller
I didn't let her hear my heart hollowing as the shirts I chose out went from low necked and cropped to Amish
And when she let the fitting room doors lock behind her over and over, leaving only a narrow gap on the floor
I encouraged her to wiggle under and get back in
Knowing that if I was careless enough to let them lock, I'd have to call over a frowning happy worker
As her bill totaled higher and higher and mine stayed at 24.99 I did not let myself hunch
I walked to the back of the store and looked for their big girl, tall girl, chubby girl tissues
But the final straw
Was when I watched my little sister poke at her stomach and thighs and butt and say "fat"
And grab at her forearms and neck and say "thin"
And then look at me and say 
"I wish
I wish I looked how you look"
And I got so, so angry that I have spent 16 years
Hating myself, absolutely detesting myself
And even when I was living with myself, constantly comparing my skeleton to hers
And now she tells me that she has spent 14 years doing the exact same thing
I get so, so angry because how am I supposed to feel beautiful now
If she looks like that and she doesn't
Why
Have I spent 16 years making myself sick to get myself healthy
If she looks healthy but still feels sick
How can I go on knowing my little sister thinks I'm beautiful
How can I leave her
Thinking she is not