quote:

She is like a tall, brick wall, I feel the comma after "tall" is unnecessary, and messes with the flow.
which withstands the fiercest blow-
how she excels through each and every day,
and soars above...the lowest low.

She, as pure as an angel, I think this line would be better if you were to take out the first "as".
has no fear, anger, or pride.
The one that everyone looks up to
surely has nothing to hide! I would suggest replacing "nothing" with "naught", for the sake of flow.

How I envy her!
She's everything that I wish I could be!
So, why did I feel that something was wrong
with the way she looked at me? I think "from" would work better than "with".

On that day she wept, and sulked alone,
didn't hide her pain and sorrow-
The day I pondered asking her "why?"
But then decided to ask tomorrow? I think this would flow better without the "then".

How was I to know, that night,
that when I greeted the next dawn,
It'd be the best day of my life
until I learned that she was gone?

"Who knew? No way!"
was all I heard them shout...
because all I could think of was the previous day, This line seems awkward. Perhaps replace it with something like: "I could only think of the previous day,"?
and shake my head in doubt.

Because she was like a tall, brick wall, As with in the first stanza, I would advise taking out that comma after "tall".
being slowly chipped away,
but no one noticed the damage done, I think this line would be better both flow and meaning-wise without the "but".
until it was too late.