Youth and Old Age in Dylan Thomas' Fern Hill

Dylan Thomas shared with us his childhood days in Fern Hill.
How does he describe his childhood
and why does he end the poem with the following lines?

And wake to the farm forever fled from the childless land.
Oh as I was young and easy in the mercy of his means,
Time held me green and dying
Though I sang in my chains like the sea.

Among School Children by William Butler Yeats

Among School Children by William Butler Yeats has once been prescribed
as one of the poems in Literature in English Programme.
Imagine, those 17 year old kids have to study this poem for their SPM examination.
I'm sure as you are older and more experience than those kids,
you would have better insights into this poem.
Please write here in this space your thoughts on Among School Children.