Always Falling Short

I know you who you wanted me to be
And I'm sorry that I'm not her
But it isn't really such a loss, right?
My parents have a better daughter

She may be a whole six years younger
But she's already prettier, and has better style
She likes wearing pink and painting her nails
And she doesn't fake her smile

Then they have my brother
He's the only boy they've got
It's a job I can not cover
For a boy is what I'm not

So I am just the guinea pig
The shadow that paves the way
The not-so-important one
With nothing interesting to say

I do my best to make you all proud
But I'm always falling short
I'm doing this all by myself
With pieces I can't sort

I'm not asking you to help me
I can build this puzzle on my own
I just want you all to understand
I only want my feelings known