I like this. A lot. A very simple idea butI think anyone who reads this will probably think of some personal experience. I did, anyway.
One suggestion though, if I may.
“The smoke is long gone and
The metal carcasses of the buildings hold
Nothing up.”
Those lines feel very wordy. Perhaps…
The smoke is long gone,
The buildings metal carcasses
Hold nothing up.
That’s just my opinion, its certainly fine how it is

eerie, but a truth was learned that day!

I like this. Everyone’s either in a hurry to grow up or mired in immaturity. Mistakes will be made.