Grin and bear it - true story and a creative writing exercise

I sit inside my car outside of the community center while my son attends an activity indoors. A gaggle of youth cluster the entry door calling to one another.  Soon a few youth hiss and charge about my car until one of them discovers I am within.
The sun settles along my windshield as I read legs crossed and tucked beneath my thighs.  The wind roars and calm rocking the vehicle.
Outside three girls rush by and one trips.  I glance up and briefly make eye contact with a girl outside.  Is your friend alright I wonder, turning my mouth into a half smile before noticing the fallen girl is rising. I return to my reading.  A girl laughs loudly and the girl who has fallen reacts to her laugh, upset.  "Why are you laughing at me for falling?" The other responds "I'm not laughing at you.  I'm laughing at the old lady in the car.  She looked at you when you fell."
Old?  Old lady?
The girl continues to laugh, taunting and daring me to look up and connect again.  I resolve to steadily gaze at my book as the girl encourages her friends to fall near the hood of my car, enticing me to respond.
I feel slighted, affronted, and betrayed. An urge to correct, lash out, make some noise of my own agitates my innards. Then I laughed at my response.  I am not young and have no reason to fell bullied by this hissing child.
Moments later the same child returns yelling at me from the doorway.  She called me an "old lady" and spewed her words across an invisible fence.
I remain still and quiet protected by the shell of steel, plastic, and glass.... shielded from the filthy excrement of a hostile youth.