My 110th English Gogyohka

If you wanted to say that your palms together are like a small cage, I would switch the the 1st and 3rd line. I think it would make more sense in English this way.

Palming a firefly
in both my hands
like a small cage

Then, I think the last 2 lines are missing just a final thought for it to make sense.
What does the quiet light from among your fingers do, how does it look or did you just want to say it is there?

For example:
the quiet light
from among my fingers...(something).

or
a quiet light
glows around my fingers.
____

Fireflys are so pretty! ^^

Sorry,teamjenny
I've forgot to write "escapes".
The fourth line is "the quiet light escapes"

Palming a firefly
in both my hands
like a small cage
the quiet light escapes
from among my fingers.

Your updated version reads fine.

You could make this change:
amoung -> between

Thank you for your good advice, Peter.

Thank you for your good advice, Peter.