The answer is blowing in the wind

She is a waif. A slight gust of wind would sweep her into oblivion.

She notices no-one and no-one notices her.

Once she was a princess, beautiful and talkative, encased in fine fabrics, protected by sturdy walls.

Now she is a silent ghost on a dirty street. Walking wherever it takes her is the only thing she know how to do, now that all her accomplishments are merely memories.

She is only a few steps from a lifetime in the gutter, and a few steps less from slitting her wrists with the first rusty blade she happens upon.