Grade my sonnet /ic/

I scratch across a sea of dead, brown leaves,
And ponder the trees, lifeless and bare.
Weather and Time work together as thieves,
Stealing life, and leaving despair.

I remember when green giants stood with pride,
Their vibrant leaves in the breeze at play.
The giants aged, and I watched as one by one the leaves died,
Vivacity has left, and now the giants slowly wither away.

But I know new vigor will spring forth in time,
Where one leaf fell, two will arise.
The height of youthful exuberance again sublime,