we real cool

I think this poem could be analyzed in two ways. Either don’t be cool, or be cool.
And this is depend on how individual understand (take) on the last line of the poem.
Let’s see line by line.

The Pool Players: yes they are cool. It is common concept that pool players are tough, cool, and guys.
Seven at the golden shovel: seven people who are real cool. This means group of cool people.
We real cool. We: poem starts out the fact that they are real cool. Not just cool.
Left school.
Lurk late. We
Strike Straight. We
Sing sin. We
Thin gin. We
Jazz June. We: these are the entire real cool things that they have done together.
Die soon : this last line maybe trying to tell readers multiple things.
One thins is that don’t be cool because you will sin, live like trash, and die soon.
Or in other hand, they(we) are so cool that they take death like nothing and they die when they are still cool so that they will be always remembered as real cool people.
However, this poem reminded me of James Dean and Kurt Cobain. And, I don’t want to be real cool. I will live long, and be just cool.